What Is an Invoice? Required Fields Under EU VAT Law

An invoice is not a request for payment. It is a document whose content is prescribed by law, because it does two things the tax system depends on: it fixes the supplier's VAT liability, and it is the evidence on which the customer deducts that same VAT. Get the content wrong and the second half breaks — which is why "missing a field" is not a formatting complaint.

In the EU, the required content is harmonized. Article 226 of Directive 2006/112/EC (the VAT Directive) sets out the particulars, and it is deliberately exhaustive: "only the following details are required for VAT purposes".

The mandatory particulars

Article 226 lists 15 numbered points plus three lettered ones added in 2010 — 18 in total:

Point	What must appear
1	The date of issue
2	A sequential number, based on one or more series, which uniquely identifies the invoice
3	The supplier's VAT identification number
4	The customer's VAT identification number, where the customer is liable for the VAT or the supply is an intra-Community supply under Article 138
5	The full name and address of both the supplier and the customer
6	The quantity and nature of the goods, or the extent and nature of the services
7	The date of supply (or of a payment on account) where it differs from the date of issue and can be determined
7a	The mention "Cash accounting" where the supplier uses that scheme
8	The taxable amount per rate or exemption, the unit price excluding VAT, and any discounts not already reflected in the unit price
9	The VAT rate applied
10	The VAT amount payable
10a	The mention "Self-billing" where the customer issues the invoice instead of the supplier
11	For an exempt supply, a reference to the applicable EU or national provision, or any other reference indicating the exemption
11a	The mention "Reverse charge" where the customer is liable for the VAT
12	For a new means of transport, the characteristics identifying it
13	"Margin scheme — Travel agents" where that scheme applies
14	"Margin scheme — Second-hand goods", "— Works of art" or "— Collector's items and antiques" as applicable
15	Where a tax representative is liable, that representative's VAT number, name and address

Three related rules matter in practice. A supplier not established in the member state of taxation, supplying under reverse charge, may omit points 8, 9 and 10 and instead describe the taxable amount by reference to quantity and nature (Article 226a). Member states may require the customer's VAT number in cases beyond point 4 (Article 227). And amounts may be expressed in any currency, provided the VAT amount payable is also given in the national currency of the member state where the tax is due (Article 230).

The exact wordings

Points 7a, 10a, 11a, 13 and 14 require literal mentions — the words themselves, not a paraphrase. This is where invoices most often fail a review, because "VAT reverse charged per Art. 196" is not the phrase the Directive names.

National law fixes the language of those mentions. Lithuania's PVMĮ Article 80 mirrors Article 226 point for point and prescribes the Lithuanian forms: „Atvirkštinis apmokestinimas" (reverse charge), „Pinigų apskaitos sistema" (cash accounting) and „Sąskaitų faktūrų išsirašymas" (self-billing).

The exemption reference in point 11 is the flexible one. It offers three alternatives — cite the Directive, cite the national provision, or give any other reference indicating exemption — and the Commission's Explanatory Notes confirm that the single word "Exempt" suffices. They also settle a common overlap: where a supply is both exempt and reverse-charged, the "Reverse charge" mention alone is enough.

When you must issue one

Article 220 sets out which supplies require an invoice: supplies to another taxable person or a non-taxable legal person, distance sales, intra-Community supplies under Article 138, and payments on account. Financial and insurance services exempt under Article 135(1)(a)–(g) need no invoice.

Article 222 harmonizes the deadline for exactly two categories:

For intra-Community supplies of goods (Article 138) and for cross-border services where the customer is liable (Article 196), the invoice must be issued no later than the fifteenth day of the month following the month in which the chargeable event occurred.

For everything else, member states set their own time limits. This asymmetry surprises people: there is no EU-wide deadline for a domestic invoice.

Simplified invoices

Not every invoice needs all 18 particulars. Under Article 220a, member states must allow a simplified invoice where:

• the invoice amount is not higher than EUR 100 (or the national-currency equivalent);
• the document amends an earlier invoice (an Article 219 document — a credit note); or
• the supplier uses the small-enterprise exemption under Article 284 — a case added by the SME scheme directive and applicable since 1 January 2025.

Under Article 238, member states may additionally allow simplification, after consulting the VAT Committee, where the amount is above EUR 100 but not above EUR 400, or where commercial practice makes full compliance particularly difficult. So whether the €400 band is available depends on the country.

A simplified invoice must still carry, per Article 226b: the date of issue; identification of the supplier; identification of the type of goods or services; the VAT amount payable or the information needed to calculate it; and, for an amending document, an unambiguous reference to the original invoice and the details being changed.

Two important limits. Simplification is never available for distance sales, exempt intra-Community supplies of goods, or cross-border reverse-charge supplies by a non-established supplier — precisely the cross-border cases where the invoice is doing tax-administration work. And member states may not demand more than Articles 226, 227 and 230 permit.

What ViDA changes

Council Directive (EU) 2025/516 — the "VAT in the Digital Age" package, in force since 14 April 2025 — rewrites much of this, mostly with effect from 1 July 2030:

• Two new particulars in Article 226. Point (16): on a corrective invoice, the sequential number of the invoice being corrected. Point (17): the supplier's bank account numbers or virtual account numbers, or any other identifiers unambiguously identifying the accounts the invoice can be paid into. (The adopted text deliberately does not say "IBAN", and a payment-date requirement that appeared in the Commission's proposal was dropped.)
• "Triangular transaction" joins the reverse-charge mention where the customer is liable under Article 197.
• "Electronic invoice" narrows. Article 217 will require a structured electronic format allowing automated processing — a plain PDF stops qualifying, while hybrid formats (structured data plus a human-readable rendering) still do.
• E-invoicing becomes the default under Article 218, referencing the European standard on electronic invoicing under Directive 2014/55/EU, and customer acceptance is no longer required for compliant invoices to businesses.
• The Article 222 deadline shortens to 10 days following the chargeable event.
• Recapitulative statements (EC Sales Lists) are abolished, replaced by digital reporting.

One change is already live: since 14 April 2025, member states may mandate domestic B2B e-invoicing without requesting a derogation — which is why national mandates have accelerated.

How Nordlet handles it

Invoices are built from structured data rather than a template, so the mandatory particulars come from the records rather than from whoever is typing. The company's name, registration code and VAT number, the partner's equivalents, sequential numbering from a per-document-type series, issue and due dates, per-line quantity, description, unit price, VAT rate, and the taxable amount and VAT amount per rate are all carried on the invoice and rendered on the PDF in Lithuanian, English or Russian.

The VAT treatment the invoice reports is resolved by the VAT engine, which is what determines whether a supply is domestic, an intra-Community supply, reverse-charged, exempt or out of scope — and therefore which of the Article 226 mentions apply. For structured exchange, the Peppol BIS 3.0 output maps the same data onto EN 16931 — the standard ViDA will make the default — and the national e-invoicing formats (Italy's FatturaPA, Poland's KSeF FA(3), Romania's CIUS-RO UBL) are generated from the same source.

Two honest notes. The literal mentions are driven by the invoice's VAT scheme, so a scheme set incorrectly produces a technically defective invoice — worth checking when you first configure cross-border sales. And simplified invoicing is not a separate document mode: invoices carry the full particulars, which is always permissible, since simplification is an option rather than an obligation.

Related reading: what a credit note must contain, and why a proforma is not an invoice at all.

FAQ

What are the mandatory fields on an EU VAT invoice?

Article 226 of the VAT Directive lists them: date of issue, a unique sequential number, the supplier's VAT number, the customer's VAT number where relevant, both parties' names and addresses, the quantity and nature of what was supplied, the supply date if different from the issue date, the taxable amount per rate, the VAT rate, the VAT amount, plus specific mentions for exemptions, reverse charge, cash accounting, self-billing and margin schemes.

Can an invoice be issued in a foreign currency?

Yes. Article 230 permits any currency, provided the VAT amount payable is also expressed in the national currency of the member state where the VAT is due, converted using the Directive's exchange-rate rules.

What is a simplified invoice and when can I use one?

A reduced-content invoice permitted for amounts up to EUR 100, for documents amending an earlier invoice, and for suppliers under the SME exemption; member states may extend it to EUR 400. It is never available for distance sales, exempt intra-Community supplies, or cross-border reverse-charge supplies by a non-established supplier.

Do I have to write "Reverse charge" exactly?

Yes — Article 226(11a) requires that literal mention, and national law fixes its wording in the local language (Lithuanian: „Atvirkštinis apmokestinimas"). A description of the mechanism instead of the prescribed phrase is a defect, even if the meaning is clear.

When must an invoice be issued?

For intra-Community supplies of goods and cross-border reverse-charge services, by the fifteenth day of the month following the chargeable event. For other supplies the deadline is set nationally. From 1 July 2030, ViDA shortens the harmonized deadline to 10 days after the chargeable event.