Firm Guides · Electronic invoicing

Electronic invoicing: practical guide

Electronic invoicing is no longer a novelty: it is the standard way to document 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 explains how the system works, the types of documents, issuance deadlines, storage (conservazione) and related compliance requirements, with the practical details that make the difference.

Update note: the rules and the penalties referred to here are those in force at the date on which this guide was updated. Thresholds, time limits and the technical specifications of the XML schema change with the annual measures of the Agenzia delle Entrate and must be checked against official sources before any application.

1. What it is and how the Sistema di Interscambio works

The electronic invoice is a file in XML format, compliant with the specifications of the Agenzia delle Entrate, transmitted through the Sistema di Interscambio (SdI), which works like a public “postman”: it receives the file from the supplier, checks its formal correctness and delivers it to the customer.

The workflow for each document is always the same:

1. The supplier prepares the XML file and signs it or transmits it through its own intermediary or software.
2. The SdI carries out the formal checks (existing VAT number (partita IVA), valid recipient code, consistency of the amounts, field format).
3. If the checks fail, the SdI issues a rejection receipt: the invoice is considered not issued and must be retransmitted corrected within 5 days, keeping the original date and number.
4. If the checks are passed, the SdI delivers the file and returns a delivery receipt (or a notice of impossibility of delivery, with deposit in the recipient’s reserved area).

Delivery takes place via the recipient code (7 characters) or the PEC notified by the customer. For customers without a VAT number (private consumers) the conventional code 0000000 is indicated and the customer is given a paper copy or a PDF copy, informing them that the original is available in their reserved area.

2. Who is required: the timeline

The obligation has been progressively extended until it became general:

Persons not established in Italy and certain specific cases remain outside the obligation. The prohibition on issuing electronic invoices via the SdI for healthcare services provided to individuals, for reasons of health-data protection, should be borne in mind: such transactions are documented on paper or electronically outside the SdI. The prohibition is no longer an annual extension: art. 2 of d.lgs. 81/2025 removed from art. 10-bis of d.l. 119/2018 the reference to individual tax periods, making it structural and therefore applicable to 2026 as well. Under art. 9-bis, comma 2, of d.l. 135/2018 the prohibition extends also to persons not required to send data to the Sistema tessera sanitaria, the Italian health card data system, for invoices relating to healthcare services provided to individuals. The obligation to transmit the data to the Sistema tessera sanitaria is unaffected.

3. Document types (TD codes)

The TipoDocumento field, the document type tag of the FatturaPA schema, qualifies the nature of the transaction and is one of the points where mistakes are most often made. The most frequently used codes:

4. Issuance deadlines

• Immediate invoice: must be transmitted to the SdI within 12 days from the date the transaction is carried out. The “Data” (date) field in the file remains that of the transaction, not that of the transmission.
• Deferred invoice: for supplies accompanied by DDT or for documented services, it is issued by the 15th day of the following month after the month in which the transaction is carried out, with a summary of the month’s transactions.

Compliance with the deadline is essential: the transaction date determines when the tax becomes chargeable and therefore the VAT settlement in which the document is included.

5. Reverse charge, self-invoices and cross-border transactions

In 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 in purchases and in sales: the integration is transmitted to the SdI with code TD16.

If the supplier does not issue the invoice within the time limit set by law, or issues it in irregular form, the customer (cessionario or committente) no longer has to pay the tax or to issue a self-invoice. For violations committed from 1 September 2024 the customer must report the omission or the irregularity to the Agenzia delle Entrate within ninety days of the deadline by which the invoice should have been issued, or of the date on which the irregular invoice was issued (art. 6, comma 8, d.lgs. 471/1997). The time limit runs from the issuing deadline, not from the date of the transaction: twelve days from the date the transaction is carried out for the immediate invoice, the 15th day of the following month for the deferred invoice. A customer who fails to do so is liable to a penalty of 70% of the tax, with a minimum of 250 euros.

The report is transmitted to the SdI with document type TD29, available since 1 April 2025. It is a mere communication: it does not allow the VAT on the purchase to be deducted, it must be completed with the details of the transaction required by art. 21, comma 2, d.P.R. 633/1972 and it carries a recipient code of seven zeros; a correction is made by transmitting a further TD29 with the opposite sign. TD20 remains the correct self-invoice in two cases only: domestic reverse charge not accounted for by the supplier (art. 6, comma 9-bis, d.lgs. 471/1997) and intra-Community or equivalent purchases where the invoice does not arrive by the end of the second month following that in which the transaction was carried out, or arrives showing consideration lower than the actual amount (art. 46, comma 5, d.l. 331/1993).

For cross-border transactions the old esterometro has been superseded: the data are communicated through the SdI. In summary:

• Purchases from abroad: the supplement or self-invoice document is transmitted with TD17 (services), TD18 (intra-Community goods) or TD19 (goods from non-residents already in Italy), by the fifteenth day of the month following that of receipt of the document.
• Supplies to abroad: a standard electronic invoice is issued indicating as recipient code XXXXXXX (seven Xs) when the foreign customer does not have an SdI channel.

6. Stamp duty

On electronic invoices with no VAT charged of an amount exceeding 77.47 euros, stamp duty is due in the amount of 2 euros. This typically concerns flat-rate taxpayers (forfettari), as well as exempt, non-taxable, out-of-scope and excluded transactions. In the XML file, the specific field “Bollo virtuale” must be filled in.

In the reserved area the Agenzia delle Entrate makes available two lists: list A, which cannot be amended, containing the invoices that state the stamp duty as paid, and list B, which the taxpayer can amend, containing those on which the duty is due but was not indicated. Amendments to list B must be made by the last day of the month following the quarter (for the second quarter the deadline moves to 10 September); the amount due is then shown in the statement in the reserved area. Payment is quarterly:

A simplification then applies, linked to the 5,000-euro threshold: if the duty due for the first quarter is less than 5,000 euros, payment may be made by 30 September; if the amount due for the first and second quarters together is less than 5,000 euros, payment may be made by 30 November, with no interest or penalties (art. 17, comma 1-bis, d.l. 124/2019, as amended by art. 3 of d.l. 73/2022). The statute says “less than”, whereas the guide of the Agenzia delle Entrate says “does not exceed”: for an amount of exactly 5,000 euros it is advisable to follow the wording of the statute and pay by the ordinary deadline. If a deadline falls on a public holiday it moves to the first following working day.

7. Statutory-compliant archiving

Electronic invoices must be archived in a statutory-compliant electronic manner for 10 years. Saving the XML files on a disk or in a folder is not sufficient: statutory-compliant archiving requires a process with a timestamp and a records-keeping manager (responsabile della conservazione), which ensures authenticity, integrity, readability and retrievability over time.

Agenzia delle Entrate offers the archiving service free of charge upon acceptance of the service agreement in the reserved area: it is a practical choice for small entities, provided that the acceptance is actually activated. Many taxpayers take archiving for granted because “the invoices are in the portal”: this is a frequent and risky misunderstanding.

8. Penalties

For violations committed from 1 September 2024 the penalties as rewritten by d.lgs. 87/2024 apply. Failure to invoice taxable transactions, or invoicing them late, is punished with a penalty of 70% of the tax on the taxable amount not correctly documented or recorded during the financial year, with a minimum of 300 euros (art. 6, commi 1 e 4, d.lgs. 471/1997). If the violation has not affected the correct settlement of the tax the penalty ranges from 250 to 2,000 euros.

For transactions that are non-taxable, exempt, outside the scope of VAT or subject to reverse charge the penalty is 5% of the consideration not documented or not recorded, subject to the same minimum of 300 euros (art. 6, comma 2, first sentence, d.lgs. 471/1997); where the violation is not relevant even for the determination of income, the fixed penalty of 250 to 2,000 euros under the second sentence applies, to which the 300-euro minimum does not apply. On the side of the customer, failure to report the omitted or irregular invoicing is punished with 70% of the tax, with a minimum of 250 euros (art. 6, comma 8).

In any case, violations can be regularised through ravvedimento operoso, with reductions that are greater the more timely the corrective action. The most delicate case remains the rejected invoice (fattura scartata) and never retransmitted: for the tax authorities that invoice is deemed never to have been issued.

9. Frequent errors and best practices

• Ignoring the SdI (Sistema di Interscambio) receipts. They must be checked systematically: an invoice rejected and not retransmitted within 5 days becomes a case of omitted issuance.
• Using the wrong TipoDocumento code, in particular for integrations under reverse charge and for purchases from abroad.
• Incorrect or missing recipient code (codice destinatario): it causes rejections or failed delivery. It must be requested and verified when setting up the customer’s master data.
• Forgetting the stamp duty (bollo) on invoices without VAT above 77.47 euros: a typical mistake by flat-rate scheme taxpayers (regime forfettario).
• Confusing the transaction date with the sending date, with effects on the VAT settlement (liquidazione IVA).
• Not activating legally compliant archiving (conservazione a norma), believing that storing it in the portal is sufficient.
• Not providing the courtesy copy to the private customer, who often does not check the reserved area.
• Still using TD20 for an invoice not received from the supplier: since 1 April 2025 the report is transmitted with TD29, within ninety days of the deadline by which the invoice should have been issued.

10. Two practical examples

Example 1 – Flat-rate scheme taxpayer (regime forfettario) invoicing an Italian company. A consultant under the flat-rate scheme issues an invoice for 1,500 euros. She uses the code TD06, does not charge VAT (indicating the transaction nature provided for the flat-rate scheme), does not apply withholding tax (ritenuta d’acconto) and, exceeding the amount of 77.47 euros, fills in the 2-euro stamp duty (bollo) . She transmits it within 12 days from the invoice date and checks the delivery receipt.

Example 2 – Purchase of a service from an EU supplier. An Italian company receives from a German supplier an invoice for consultancy services, without VAT. The company must integrate the document with Italian VAT and transmit to the SdI (Sistema di Interscambio, Italian e-invoicing platform) a file with code TD17 by the fifteenth day of the month following receipt, recording it both among purchases and among sales. Omitting this step means you have not fulfilled the communication of cross-border transactions.

In summary

E-invoicing rewards method: complete and verified customer master data, systematic checking of SdI receipts, attention to the document type, compliant archiving (conservazione a norma) that is actually active, and oversight of the stamp duty (bollo). These are simple measures that prevent almost all issues. Studio Ponchio is available to help set up the invoicing cycle, verify reverse-charge integrations, and manage compliant archiving.

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