The electronic invoice is no longer a novelty: it is the ordinary way of documenting transactions in Italy. Yet it remains one of the areas where the most formal errors are made, with consequences ranging from rejection of the document to penalties. This guide sets out how the system works, the document types, the issuing deadlines, compliant archiving and the related obligations, together with the practical points that make the difference.
Note on updates: the structural rules described here are settled. The items marked “(to be confirmed)” depend on extensions or annual measures and must be checked against the official sources before being applied.
1. What the Sistema di Interscambio is and how it works
The electronic invoice is an XML file complying with the specifications of the Agenzia delle Entrate (Italian Revenue Agency), transmitted through the Sistema di Interscambio (SdI, the public exchange system), which acts as a public “postman”: it receives the file from the supplier, checks that it is formally correct and delivers it to the customer.
Every document follows the same route:
The supplier prepares the XML file and signs it, or transmits it through its intermediary or software.
The SdI performs formal checks (existing VAT number, valid recipient code, consistency of the amounts, field formats).
If the checks fail, the SdI issues a rejection receipt: the invoice is treated as never issued and must be corrected and resent within 5 days, keeping its original date and number.
If the checks are passed, the SdI delivers the file and returns a delivery receipt (or a failed-delivery receipt, with the file placed in the recipient’s private area).
Delivery takes place through the codice destinatario (recipient code, 7 characters) or the PEC certified email address notified by the customer. For customers without a VAT number (private consumers) the conventional code 0000000 is used and the customer is given a paper or PDF copy, with a note that the original is available in their private area.
2. Who is required to comply: the timeline
The obligation was extended step by step until it became general:
From
Who is covered
2014
Supplies to public authorities
1 January 2019
All VAT taxable persons, B2B and B2C transactions
1 July 2022
Taxpayers under the regime forfettario and the minimum-taxpayer regime with revenue or fees above 25.000 euro in the previous year
1 January 2024
All taxpayers under the regime forfettario, with no exemption threshold left
Persons not established in Italy and a few special cases remain outside the obligation. It is worth recalling the prohibition on issuing electronic invoices through the SdI for healthcare services provided to individuals, to protect health data: those transactions are documented on paper or electronically outside the SdI (the measure has been extended year by year: to be confirmed for 2026).
3. Document types (TD codes)
The TipoDocumento field identifies the nature of the transaction and is one of the points where mistakes are most common. The most frequently used codes:
Code
Document
When it is used
TD01
Invoice
The ordinary case of a supply of goods or services
TD02
Payment on account or advance against an invoice
Payment made in advance of the transaction
TD04
Credit note
Full or partial reversal of an invoice
TD05
Debit note
Upward adjustment of an invoice
TD06
Professional fee note
Self-employment fees
TD16
Domestic reverse charge integration
Purchases under the reverse charge from Italian suppliers
TD17
Integration or self-billed invoice for services from abroad
Purchase of services from EU and non-EU persons
TD18
Integration for intra-EU acquisitions of goods
Purchases of goods from EU suppliers
TD19
Integration or self-billed invoice under art. 17(2)
Purchase of goods from non-residents already located in Italy
TD20
Self-billed invoice to regularise a position
Invoice not received from the supplier, or received in an irregular form
TD24
Deferred invoice
Supplies accompanied by a delivery note (DDT) or documented services
TD27
Own consumption or free-of-charge supplies
Use for purposes unrelated to the business
4. Issuing deadlines
Immediate invoice: it must be transmitted to the SdI within 12 days of the date the transaction took place. The “Data” field of the file remains the date of the transaction, not the date it was sent.
Deferred invoice: for supplies accompanied by a delivery note (DDT), or for documented services, it is issued by the 15th of the month following the one in which the transaction took place, summarising that month’s transactions.
Meeting the deadline is essential: the date of the transaction determines when the tax becomes chargeable and therefore which VAT settlement the document falls into.
5. Reverse charge, self-billed invoices and cross-border transactions
Under the domestic reverse charge the supplier issues an invoice without VAT and the customer integrates the document with the rate and the tax, recording it both among purchases and among sales: the integration is transmitted to the SdI with code TD16.
For cross-border transactions the old esterometro report has been superseded: the data is reported through the SdI. In short:
Purchases from abroad: the integration document or self-billed invoice is transmitted with TD17 (services), TD18 (intra-EU goods) or TD19 (goods from non-residents already in Italy), by the fifteenth day of the month following the one in which the document was received.
Supplies to customers abroad: a regular electronic invoice is issued with recipient code XXXXXXX (seven Xs) where the foreign customer has no SdI channel.
6. Stamp duty
Electronic invoices issued without charging VAT for an amount above 77,47 euro attract 2 euro of imposta di bollo (Italian stamp duty). This typically concerns taxpayers under the regime forfettario and exempt, zero-rated, out-of-scope and excluded transactions. The dedicated “Bollo virtuale” field must be filled in the XML file.
The Revenue Agency makes available in the taxpayer’s private area a statement of the amounts due, computed on the invoices transmitted. Payment is quarterly, with a simplification rule: if the amount due for the first quarter does not exceed a minimum threshold, payment may be deferred and combined with the following quarters (thresholds and deadlines to be confirmed for 2026).
7. Compliant electronic archiving
Electronic invoices must be kept in compliant electronic archiving for 10 years. Saving the XML files on a disk or in a folder is not enough: compliant archiving requires a process with a time stamp and a designated archiving officer, guaranteeing authenticity, integrity, legibility and retrievability over time.
The Agenzia delle Entrate offers the archiving service free of charge, subject to accepting the service agreement in the private area: it is a practical choice for small businesses, provided the acceptance has actually been completed. Many taxpayers take archiving for granted because “the invoices are on the portal”: that is a common and risky misunderstanding.
8. Penalties
Failure to issue an electronic invoice, or issuing it late, is penalised in proportion to the tax not properly documented, with a minimum for each transaction; where the breach does not affect the VAT settlement, the penalty is fixed and reduced. The amounts were revised by the reform of the penalty system (D.Lgs. 87/2024) for violations committed from 1 September 2024 (exact amounts to be confirmed).
In any event, breaches can be regularised through ravvedimento operoso (voluntary settlement), with larger reductions the sooner you act. The most delicate case remains the rejected invoice that is never resent: for the tax authorities, that invoice was never issued.
9. Frequent mistakes and good practice
Ignoring the SdI receipts. They must be checked systematically: an invoice that is rejected and not resent within 5 days counts as an invoice never issued.
Getting the TipoDocumento code wrong, particularly on reverse charge integrations and purchases from abroad.
A wrong or missing recipient code: it causes rejections or failed deliveries. It should be requested and checked when the customer record is created.
Forgetting the stamp duty on invoices without VAT above 77,47 euro: a typical mistake among taxpayers on the regime forfettario.
Confusing the date of the transaction with the date of transmission, which affects the VAT settlement.
Not activating compliant archiving, in the belief that storage on the portal is enough.
Not giving the courtesy copy to a private customer, who often never looks at their private area.
Not regularising with a TD20 when the supplier fails to issue the invoice due.
10. Two practical examples
Example 1 – A regime forfettario taxpayer invoicing an Italian company. A consultant on the regime forfettario issues a fee note of 1.500 euro. She uses code TD06, shows no VAT (stating the nature-of-transaction code provided for the regime forfettario), applies no withholding tax and, as the amount exceeds 77,47 euro, fills in the 2 euro stamp duty. She transmits within 12 days of the date of the fee note and checks the delivery receipt.
Example 2 – Purchase of a service from an EU supplier. An Italian business receives from a German supplier an invoice for consultancy services, without VAT. The business must integrate the document with Italian VAT and transmit to the SdI a file with code TD17 by the fifteenth day of the month following receipt, recording it both among purchases and among sales. Skipping this step means the cross-border reporting obligation has not been met.
In summary
Electronic invoicing rewards method: complete and verified customer records, systematic checking of the SdI receipts, care with the document type, compliant archiving actually switched on, and keeping an eye on stamp duty. These are simple precautions that avoid almost every problem. Studio Antolini is available to set up your invoicing cycle, check reverse charge integrations and manage compliant archiving.
Electronic invoicing: a practical guide
The electronic invoice is no longer a novelty: it is the ordinary way of documenting transactions in Italy. Yet it remains one of the areas where the most formal errors are made, with consequences ranging from rejection of the document to penalties. This guide sets out how the system works, the document types, the issuing deadlines, compliant archiving and the related obligations, together with the practical points that make the difference.
Note on updates: the structural rules described here are settled. The items marked “(to be confirmed)” depend on extensions or annual measures and must be checked against the official sources before being applied.
1. What the Sistema di Interscambio is and how it works
The electronic invoice is an XML file complying with the specifications of the Agenzia delle Entrate (Italian Revenue Agency), transmitted through the Sistema di Interscambio (SdI, the public exchange system), which acts as a public “postman”: it receives the file from the supplier, checks that it is formally correct and delivers it to the customer.
Every document follows the same route:
The supplier prepares the XML file and signs it, or transmits it through its intermediary or software.
The SdI performs formal checks (existing VAT number, valid recipient code, consistency of the amounts, field formats).
If the checks fail, the SdI issues a rejection receipt: the invoice is treated as never issued and must be corrected and resent within 5 days, keeping its original date and number.
If the checks are passed, the SdI delivers the file and returns a delivery receipt (or a failed-delivery receipt, with the file placed in the recipient’s private area).
Delivery takes place through the codice destinatario (recipient code, 7 characters) or the PEC certified email address notified by the customer. For customers without a VAT number (private consumers) the conventional code 0000000 is used and the customer is given a paper or PDF copy, with a note that the original is available in their private area.
2. Who is required to comply: the timeline
The obligation was extended step by step until it became general:
From
Who is covered
2014
Supplies to public authorities
1 January 2019
All VAT taxable persons, B2B and B2C transactions
1 July 2022
Taxpayers under the regime forfettario and the minimum-taxpayer regime with revenue or fees above 25.000 euro in the previous year
1 January 2024
All taxpayers under the regime forfettario, with no exemption threshold left
Persons not established in Italy and a few special cases remain outside the obligation. It is worth recalling the prohibition on issuing electronic invoices through the SdI for healthcare services provided to individuals, to protect health data: those transactions are documented on paper or electronically outside the SdI (the measure has been extended year by year: to be confirmed for 2026).
3. Document types (TD codes)
The TipoDocumento field identifies the nature of the transaction and is one of the points where mistakes are most common. The most frequently used codes:
Code
Document
When it is used
TD01
Invoice
The ordinary case of a supply of goods or services
TD02
Payment on account or advance against an invoice
Payment made in advance of the transaction
TD04
Credit note
Full or partial reversal of an invoice
TD05
Debit note
Upward adjustment of an invoice
TD06
Professional fee note
Self-employment fees
TD16
Domestic reverse charge integration
Purchases under the reverse charge from Italian suppliers
TD17
Integration or self-billed invoice for services from abroad
Purchase of services from EU and non-EU persons
TD18
Integration for intra-EU acquisitions of goods
Purchases of goods from EU suppliers
TD19
Integration or self-billed invoice under art. 17(2)
Purchase of goods from non-residents already located in Italy
TD20
Self-billed invoice to regularise a position
Invoice not received from the supplier, or received in an irregular form
TD24
Deferred invoice
Supplies accompanied by a delivery note (DDT) or documented services
TD27
Own consumption or free-of-charge supplies
Use for purposes unrelated to the business
4. Issuing deadlines
Immediate invoice: it must be transmitted to the SdI within 12 days of the date the transaction took place. The “Data” field of the file remains the date of the transaction, not the date it was sent.
Deferred invoice: for supplies accompanied by a delivery note (DDT), or for documented services, it is issued by the 15th of the month following the one in which the transaction took place, summarising that month’s transactions.
Meeting the deadline is essential: the date of the transaction determines when the tax becomes chargeable and therefore which VAT settlement the document falls into.
5. Reverse charge, self-billed invoices and cross-border transactions
Under the domestic reverse charge the supplier issues an invoice without VAT and the customer integrates the document with the rate and the tax, recording it both among purchases and among sales: the integration is transmitted to the SdI with code TD16.
For cross-border transactions the old esterometro report has been superseded: the data is reported through the SdI. In short:
Purchases from abroad: the integration document or self-billed invoice is transmitted with TD17 (services), TD18 (intra-EU goods) or TD19 (goods from non-residents already in Italy), by the fifteenth day of the month following the one in which the document was received.
Supplies to customers abroad: a regular electronic invoice is issued with recipient code XXXXXXX (seven Xs) where the foreign customer has no SdI channel.
6. Stamp duty
Electronic invoices issued without charging VAT for an amount above 77,47 euro attract 2 euro of imposta di bollo (Italian stamp duty). This typically concerns taxpayers under the regime forfettario and exempt, zero-rated, out-of-scope and excluded transactions. The dedicated “Bollo virtuale” field must be filled in the XML file.
The Revenue Agency makes available in the taxpayer’s private area a statement of the amounts due, computed on the invoices transmitted. Payment is quarterly, with a simplification rule: if the amount due for the first quarter does not exceed a minimum threshold, payment may be deferred and combined with the following quarters (thresholds and deadlines to be confirmed for 2026).
7. Compliant electronic archiving
Electronic invoices must be kept in compliant electronic archiving for 10 years. Saving the XML files on a disk or in a folder is not enough: compliant archiving requires a process with a time stamp and a designated archiving officer, guaranteeing authenticity, integrity, legibility and retrievability over time.
The Agenzia delle Entrate offers the archiving service free of charge, subject to accepting the service agreement in the private area: it is a practical choice for small businesses, provided the acceptance has actually been completed. Many taxpayers take archiving for granted because “the invoices are on the portal”: that is a common and risky misunderstanding.
8. Penalties
Failure to issue an electronic invoice, or issuing it late, is penalised in proportion to the tax not properly documented, with a minimum for each transaction; where the breach does not affect the VAT settlement, the penalty is fixed and reduced. The amounts were revised by the reform of the penalty system (D.Lgs. 87/2024) for violations committed from 1 September 2024 (exact amounts to be confirmed).
In any event, breaches can be regularised through ravvedimento operoso (voluntary settlement), with larger reductions the sooner you act. The most delicate case remains the rejected invoice that is never resent: for the tax authorities, that invoice was never issued.
9. Frequent mistakes and good practice
Ignoring the SdI receipts. They must be checked systematically: an invoice that is rejected and not resent within 5 days counts as an invoice never issued.
Getting the TipoDocumento code wrong, particularly on reverse charge integrations and purchases from abroad.
A wrong or missing recipient code: it causes rejections or failed deliveries. It should be requested and checked when the customer record is created.
Forgetting the stamp duty on invoices without VAT above 77,47 euro: a typical mistake among taxpayers on the regime forfettario.
Confusing the date of the transaction with the date of transmission, which affects the VAT settlement.
Not activating compliant archiving, in the belief that storage on the portal is enough.
Not giving the courtesy copy to a private customer, who often never looks at their private area.
Not regularising with a TD20 when the supplier fails to issue the invoice due.
10. Two practical examples
Example 1 – A regime forfettario taxpayer invoicing an Italian company. A consultant on the regime forfettario issues a fee note of 1.500 euro. She uses code TD06, shows no VAT (stating the nature-of-transaction code provided for the regime forfettario), applies no withholding tax and, as the amount exceeds 77,47 euro, fills in the 2 euro stamp duty. She transmits within 12 days of the date of the fee note and checks the delivery receipt.
Example 2 – Purchase of a service from an EU supplier. An Italian business receives from a German supplier an invoice for consultancy services, without VAT. The business must integrate the document with Italian VAT and transmit to the SdI a file with code TD17 by the fifteenth day of the month following receipt, recording it both among purchases and among sales. Skipping this step means the cross-border reporting obligation has not been met.
In summary
Electronic invoicing rewards method: complete and verified customer records, systematic checking of the SdI receipts, care with the document type, compliant archiving actually switched on, and keeping an eye on stamp duty. These are simple precautions that avoid almost every problem. Studio Antolini is available to set up your invoicing cycle, check reverse charge integrations and manage compliant archiving.
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