E-Invoicing Explained: EN 16931, ViDA and Influential Mandates

Our e-invoicing guide breaks down the specifics of EN 16931, the role of the EU’s ViDA legislative package and the mandates leading the charge.

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What is EInvoicing Hero

“It’s just digitising PDFs.”

E-invoicing is the victim of this common misunderstanding. E-invoicing is the exchange of invoice data in structured, machine-readable formats which are validated against rules. In many countries, e-invoices are transmitted through approved networks and platforms, enabling tax authorities to process reporting more quickly and reliably.

E-invoicing is gathering pace for two main reasons:

1. Governments worldwide want better VAT and tax visibility.

2. Organisations want faster cash collection, less manual effort and fewer disputes.

But it is possible to underestimate the role e-invoicing will play in the years to come. It’s not a compliance hoop to jump through, as much as it may feel like it. Getting it right will have a tangible impact on your business’s bottom line. The ‘winners’ are those who treat e-invoicing as a compliance programme and an upgrade to their organisation’s day-to-day operations.

What is e-invoicing?

E-invoicing is the generation and exchange of invoices in a structured format, allowing the recipient’s system to process e-invoices automatically. Universal Business Language (UBL), Cross-Industry Invoice (CII) and PEPPOL BIS are commonly used standards and frameworks for e-invoicing.

Structured e-invoicing has three requirements:

  • A compliant data model and format, often aligning to EN 16931 in Europe.
  • A delivery and exchange mechanism (such as Peppol networks, clearance platforms or state-approved platforms).
  • Stricter data and timing requirements - often linked to obligations for near real-time reporting to tax authorities.

What is EN 16931?

EN 16931 standardises e-invoicing across EU member states to increase efficiency and harmonisation in B2B, B2G and G2G transactions. It establishes a unified semantic data model for e-invoices to ensure interoperability and ease of understanding invoice content regardless of the system used. The standard requires the use of different syntaxes, such as UBL and UN/CEFACT CII.

 

What are the benefits of EN 16931?

EN 16931 simplifies processes by providing businesses with a single, common framework for e-invoicing across Europe, making cross-border transactions far less of a headache because invoices can move between countries without being rebuilt from scratch each time.

Adhering to the framework also leads to cost savings as it lowers administrative costs. Finance teams no longer spend hours each week juggling multiple invoicing formats, giving them more time to concentrate on tasks that move the business forward.

The ‘winners’ aren’t the businesses that reluctantly comply with EN 16931, but the ones that use it as an opportunity to overhaul how finance operations actually run. When invoice data is transmitted in a consistent, structured format, it flows into ERP or accounts payable systems without requiring time-consuming manual entry. This means fewer errors, faster approvals and cleaner reconciliation when the end of the month rolls around.

Treated as an opportunity, EN 16931 becomes less of a compliance burden and more of a lever for faster cash collection and fewer disputes with suppliers and customers.

Which countries have made e-invoicing mandatory?

In many countries, e-invoicing is a legal requirement for B2G and B2B entities. Several countries already require invoices to be issued as structured data and, in many cases, validated or reported through government-approved systems.

This is most visible in the clearance or near-real-time control models preferred by some countries. Under these models, the invoice is seen as compliant only after it passes through the mandated platform.

Let’s explore what these mandatory e-invoicing mandates look like in each country:

Australia

Australia’s e-invoicing mandate is a partial B2G mandate, but it’s a clear example of how public sector rules can encourage the wider market to change its processes. Since July 2022, all federal Non-Corporate Commonwealth Entities have been required to receive Peppol e-invoices in the PINT A-NZ format, with further adoption milestones running through 2026.

Brazil

Brazil has one of the most mature clearance-based e-invoicing mandates in the world – the country published its first e-invoicing legislation in 2005. Today, e-invoicing is mandatory for all established businesses in Brazil, with a well-established clearance model that uses NF-e for goods, NFS-e for services and CT-e for transport.

China

China’s nationwide rollout of e-invoicing expanded in December 2024, building on earlier pilots. The State Taxation Administration is using the programme to move away from the paper fapiao processes that invoicing has relied on for decades.

Denmark

Denmark’s B2G mandate has been in place since 2005, making it one of the earliest in the world alongside Brazil. B2G e-invoicing is mandatory via NemHandel and Peppol using OIOUBL or Peppol BIS Billing 3.0. There is no B2B mandate currently, but Denmark’s public sector e-invoicing infrastructure is so robust that other countries are following its example for their own mandates.

Greenland

Greenland’s B2G mandate came into effect in March 2025, built on Denmark’s NemHandel infrastructure. Public authorities must register with the NemHandelRegister, which is overseen by the Danish Business Authority, and provide contracting details to allow for efficient invoice processing.

Mexico

Mexico’s CFDI clearance model became universally mandatory in January 2014. The mandate now covers B2B, B2C and B2G transactions, making it one of the broadest mandates anywhere in the world.

Invoices use CFDI XML, CFDI 4.0, and are validated through certified providers of authorised certification, PACs, before they can be considered compliant.

Romania

Domestic B2B and B2G e-invoicing, done through the RO e-Factura system, became mandatory in January 2024, with full clearance exchange through the platform from July 2024. In January 2025, B2C transactions also came into scope.

Serbia

Serbia’s mandatory B2B and B2G e-invoicing mandate, which uses the national Sistem e-Faktura, SEF, came into effect in January 2023. Rules for stricter VAT recording and transactional reporting continue to expand throughout 2026.

Slovenia

Slovenia’s B2G mandate has been in place since January 2015 and requires structured formats for public sector invoicing through the Public Payments’ Administration, PPA.

South Korea

South Korea’s e-invoicing system, which operates on a pre-clearance model, was introduced in 2011. Since then, more B2G and B2B entities have been brought into the scope of the regulations.

Sweden

Sweden’s B2G mandate for public procurement came into effect in 2019, and like Denmark, it sits near the top of the Peppol adoption rankings. Suppliers are required to send invoices in the Peppol BIS Billing 3.0 format.

Taiwan

Taiwan’s Electronic Government Uniform Invoices, known as eGUI, became mandatory in January 2021 for all tax-registered entities, B2B and B2C. In January 2024, all invoices had to use the MIG 4.0 XML format.

Turkey

Turkey’s extensive e-invoicing mandate, which began in 2014, covers B2B, B2G, B2C and taxpayers. The system uses a real-time clearance model for B2B transactions, e-Fatura, and next-day reporting for B2C and other invoices, e-Arşiv.

Ukraine

Ukraine’s e-invoicing regulations, which came into effect in 2015, require tax invoices to be submitted electronically to the national VAT control platform. It isn’t a universal B2B e-invoicing requirement that covers all commercial invoices, unlike the clearance models used elsewhere.

The complete guide to 2026 and 2027's e-invoicing mandates

E-invoicing mandates are live in over 60 countries and counting, but 2026 and 2027 are something of a tipping point. This guide covers every major e-invoicing mandate coming into effect in 2026 and 2027, country by country.
2026 and 2027 E-Invoicing Mandates

Why is 2026 a tipping point for e-invoicing?

This year, dozens of countries are introducing mandatory e-invoicing. B2G mandates are pulling B2B along behind them, and ViDA will pull the EU’s many national frameworks into a more harmonised system by the end of the decade. 

The organisations that do well in this environment of regulatory change will be the ones that stop treating each mandate as an isolated project and turn to a reliable e-invoicing system that makes compliance simple.

Are there e-invoicing mandates your organisation needs to prepare for? Read our 2026/27 e-invoicing timeline guide. For practical guidance on preparing for upcoming mandates, read our guide outlining the case for a unified e-invoicing approach.