What Is E-Invoicing? Mandates, Formats and What Small Businesses Need to Know

E-invoicing means issuing and receiving invoices as structured data that software can read automatically, rather than as a document a person has to read. The invoice is created in a standard format (such as XML following the European standard EN 16931, UBL, or a national format) and transmitted through an approved network or platform.

A PDF sent by email is technically an "electronic invoice", but it's not an e-invoice in the regulatory sense, because a computer can't reliably extract the data from it.

Why governments are mandating it

• Tax compliance. Real-time or near-real-time invoice data helps tax authorities close the VAT gap.
• Efficiency. Structured invoices can be processed without manual keying, reducing errors and payment delays.
• Fraud prevention. It's harder to fake invoices that flow through a monitored system.

Where it's required (as of September 2026)

Rules and dates change, so check official sources for your country. Broadly:

• Italy has required B2B e-invoicing through its SdI platform since 2019.
• Germany has required all businesses to be able to receive structured e-invoices for domestic B2B sales since 1 January 2025. Businesses with turnover above €800,000 must issue them from 1 January 2027, and all businesses from 1 January 2028.
• Belgium has required structured e-invoices for domestic B2B transactions since 1 January 2026.
• Poland's national KSeF system became mandatory in 2026: from 1 February for the largest taxpayers and from 1 April for most others.
• France began its rollout on 1 September 2026: all VAT-registered businesses must now be able to receive e-invoices, and large and mid-sized companies must issue them. Small and micro businesses must issue them from 1 September 2027.
• EU-wide, the VAT in the Digital Age (ViDA) package will require e-invoicing and digital reporting for cross-border B2B transactions within the EU from 1 July 2030, and lets member states introduce domestic mandates without special permission.
• Outside Europe, e-invoicing or real-time invoice reporting is required in various forms in countries including Mexico, Brazil, India (for larger businesses), Saudi Arabia and others.

The UK and US have no general e-invoicing mandate for private businesses at the time of writing, though both have been consulting on and encouraging adoption.

What it means for a small business

If you're in the US, UK, Australia or most other countries, and you sell domestically or to clients outside the mandate countries, a clear PDF invoice is still perfectly acceptable.

If you sell to businesses in a mandate country, your customers may ask you to send e-invoices, particularly as their obligations to receive them kick in. They may point you to a portal or network (such as Peppol) where you can submit invoices.

If you're established in a mandate country, you'll need accounting or invoicing software, or a service provider, that can create and send compliant e-invoices. A PDF generator (including this one) won't be enough for invoices that fall under the mandate.

Formats you'll hear about

• EN 16931: the European semantic standard for e-invoices
• UBL and CII: XML syntaxes used to implement it
• Peppol: an international network and specification for exchanging e-invoices, widely used in Europe, Australia, New Zealand, Singapore and elsewhere
• Factur-X / ZUGFeRD: hybrid formats that combine a readable PDF with embedded XML data (used in France and Germany)
• FatturaPA (Italy), KSeF (Poland): national formats and platforms

Is a PDF still OK?

For most freelancers and small businesses outside the mandate countries: yes. For invoices you issue under an e-invoicing mandate: no, you need a compliant structured format, sent through the right channel. When in doubt, ask your customer's accounts team what they can accept, and ask your accountant what applies to you.

Getting ready

• Check whether any of your customers are in mandate countries and what they expect.
• If you're in one, choose software that supports your country's format and is connected to the relevant network or platform.
• Keep your customer master data clean: correct legal names, addresses and VAT numbers matter more when machines validate them.
• Don't wait for the deadline: platforms get busy close to go-live dates.