Required invoice fields: VAT invoices and EN 16931

Three layers of requirements

What an invoice must contain comes from three layers that overlap. The first is tax law: in the EU, the VAT Directive lists the particulars of a VAT invoice, and each Member State may add or relax details. The second is the e-invoicing standard: EN 16931 defines the business terms that an electronic invoice must carry. The third is the network or recipient profile, such as Peppol BIS Billing 3.0, which can require more than the standard does.

The usual categories of information

Most jurisdictions expect an invoice to cover the following kinds of information, although exact wording and thresholds vary.

• Identification: a unique invoice number, the issue date and the document type, such as invoice or credit note.
• Parties: the legal names and addresses of the seller and the buyer, and the seller's tax identifier where registered.
• What was supplied: a description, the quantity and the unit price for each line, and the date or period of supply.
• Amounts: the net amount per tax rate, the tax rate or category, the tax amount, and the total payable.
• Tax treatment: for exempt, zero-rated, reverse-charge or out-of-scope supplies, the category and the reason.
• Payment: the due date or terms, and the account details to pay into.

What an e-invoice adds

A structured invoice must also be self-consistent. Line amounts must add up to the totals, each tax category must have its own breakdown, and codes must come from the permitted lists, for example for currency, country, unit of measure and tax category. Peppol BIS Billing 3.0 additionally expects electronic addresses for both parties and a buyer reference or order reference so the recipient's system can route the invoice. A PDF that looks complete can still fail these checks, which is why validation before sending is useful.

None of this replaces advice. Check your national tax authority for the exact particulars required on invoices where you operate.