e-Invoicing Explained: Your Questions Answered

Q: What is an e-invoice?

An **e-invoice** is a structured digital document that is created, transmitted, and processed entirely by software - without anyone needing to re-key data. Unlike a scanned paper invoice or an emailed PDF, an e-invoice carries its data in a machine-readable format (typically XML) so that the sender's system and the receiver's system can talk to each other automatically. Think of it this way: a paper invoice is a picture of data, whereas an e-invoice **is** the data. Fields like supplier VAT number, line-item amounts, and payment terms are tagged and labelled, which means they can be validated, routed, and booked into an ERP without human intervention. Governments worldwide are adopting e-invoicing mandates because structured data makes tax reporting faster and fraud harder to hide. [Italy's FatturaPA system](/country/IT) was among the first large-scale B2B mandates; dozens of countries have followed, and the [global overview](/overview) shows how quickly the map is changing.

Q: How does an e-invoice differ from a PDF?

A **PDF invoice** is essentially a digital printout. The file is binary, optimised for on-screen viewing or printing, and any data inside it is locked into a visual layout. To extract line items or VAT totals from a PDF, you need optical character recognition (OCR) or manual data entry - both of which are slow and error-prone. An **e-invoice**, by contrast, is structured text. Each piece of information sits inside a clearly labelled field, so receiving software can read the invoice amount, currency, tax breakdown, and payment details instantly. No OCR, no re-keying, no misread digits. Some hybrid formats - such as Germany's **ZUGFeRD** - embed a structured XML file inside a PDF so that humans can still read the visual version while machines process the data layer. But when regulators talk about "e-invoicing mandates", they almost always mean the structured data component, not the PDF wrapper.

Q: What formats are used for e-invoicing?

The two broad families are **EDI** and **XML**. EDI formats - EDIFACT INVOIC (dominant in Europe) and ANSI X12 810 (dominant in North America) - have been in use since the 1970s for high-volume, business-to-business messaging. They remain deeply embedded in retail, automotive, and logistics supply chains. **XML-based formats** are newer and increasingly preferred by governments. The two main standards are **UBL** (Universal Business Language), developed by OASIS, and **CII** (Cross-Industry Invoice), maintained by UN/CEFACT. Both are recognised syntaxes under the European standard [EN 16931](/blog/en-16931-explained), which defines the semantic data model that all public-sector e-invoices in the EU must follow. In practice, most EU mandates converge on UBL or CII. Belgium's B2B mandate, effective 1 January 2026, requires EN 16931 invoices delivered via [Peppol](/blog/what-is-peppol). [Germany's phased B2B mandate](/guides/germany-e-invoicing) started on 1 January 2025 with mandatory reception and will require full sending capability by 2028. The EU's ViDA regulation, adopted on 11 March 2025, is driving further harmonisation across all member states by 2030-2035.

Q: How are e-invoices transmitted?

The simplest method is **email** - attaching an XML file to a message and sending it to the buyer's inbox. This works for low volumes but offers no delivery guarantees, no automated acknowledgement, and limited security. More established channels include **FTP/SFTP** (batch file transfer over secure connections), **AS2** (used widely in EDI), and **AS4** (its modern, web-services-based successor). Many tax authorities also run **web portals** where suppliers upload invoices manually, and a growing number expose **APIs** for real-time system-to-system integration. The most significant development is the rise of open e-invoicing networks, above all [Peppol](/blog/what-is-peppol). In a network model, each party connects to a certified Access Point; the network handles discovery, routing, and delivery. This "connect once, reach everyone" approach is rapidly replacing point-to-point setups, especially in countries with government mandates.

What is an e-invoice?

An e-invoice is structured data, not a picture of data. It can be validated, routed, and booked without human intervention.

An e-invoice is a structured digital document that is created, transmitted, and processed entirely by software - without anyone needing to re-key data. Unlike a scanned paper invoice or an emailed PDF, an e-invoice carries its data in a machine-readable format (typically XML) so that the sender's system and the receiver's system can talk to each other automatically.

Think of it this way: a paper invoice is a picture of data, whereas an e-invoice is the data. Fields like supplier VAT number, line-item amounts, and payment terms are tagged and labelled, which means they can be validated, routed, and booked into an ERP without human intervention.

Governments worldwide are adopting e-invoicing mandates because structured data makes tax reporting faster and fraud harder to hide. Italy's FatturaPA system was among the first large-scale B2B mandates; dozens of countries have followed, and the global overview shows how quickly the map is changing.

How does an e-invoice differ from a PDF?

A PDF invoice is essentially a digital printout. The file is binary, optimised for on-screen viewing or printing, and any data inside it is locked into a visual layout. To extract line items or VAT totals from a PDF, you need optical character recognition (OCR) or manual data entry - both of which are slow and error-prone.

An e-invoice, by contrast, is structured text. Each piece of information sits inside a clearly labelled field, so receiving software can read the invoice amount, currency, tax breakdown, and payment details instantly. No OCR, no re-keying, no misread digits.

Some hybrid formats - such as Germany's ZUGFeRD - embed a structured XML file inside a PDF so that humans can still read the visual version while machines process the data layer. But when regulators talk about "e-invoicing mandates", they almost always mean the structured data component, not the PDF wrapper.

What formats are used for e-invoicing?

The two broad families are EDI and XML. EDI formats - EDIFACT INVOIC (dominant in Europe) and ANSI X12 810 (dominant in North America) - have been in use since the 1970s for high-volume, business-to-business messaging. They remain deeply embedded in retail, automotive, and logistics supply chains.

XML-based formats are newer and increasingly preferred by governments. The two main standards are UBL (Universal Business Language), developed by OASIS, and CII (Cross-Industry Invoice), maintained by UN/CEFACT. Both are recognised syntaxes under the European standard EN 16931, which defines the semantic data model that all public-sector e-invoices in the EU must follow.

In practice, most EU mandates converge on UBL or CII. Belgium's B2B mandate, effective 1 January 2026, requires EN 16931 invoices delivered via Peppol. Germany's phased B2B mandate started on 1 January 2025 with mandatory reception and will require full sending capability by 2028. The EU's ViDA regulation, adopted on 11 March 2025, is driving further harmonisation across all member states by 2030-2035.

How are e-invoices transmitted?

Open e-invoicing networks like Peppol are replacing point-to-point setups: connect once, reach everyone.

The simplest method is email - attaching an XML file to a message and sending it to the buyer's inbox. This works for low volumes but offers no delivery guarantees, no automated acknowledgement, and limited security.

More established channels include FTP/SFTP (batch file transfer over secure connections), AS2 (used widely in EDI), and AS4 (its modern, web-services-based successor). Many tax authorities also run web portals where suppliers upload invoices manually, and a growing number expose APIs for real-time system-to-system integration.

The most significant development is the rise of open e-invoicing networks, above all Peppol. In a network model, each party connects to a certified Access Point; the network handles discovery, routing, and delivery. This "connect once, reach everyone" approach is rapidly replacing point-to-point setups, especially in countries with government mandates.

What software do you need?

At the basic end, a small business sending invoices to a single government portal might get by with a free web form or a lightweight desktop tool. But as soon as you deal with multiple countries, formats, or high volumes, you need something more capable.

Most mid-sized and large organisations handle e-invoicing through their ERP system (SAP, Oracle, Microsoft Dynamics, and others all have e-invoicing modules) or through a dedicated cloud platform that sits between the ERP and the outside world. These platforms handle format conversion, validation, transmission, and archiving - so your internal systems don't need to speak every national format natively.

Choosing the right solution depends on how many countries you operate in, how many invoices you send and receive each month, and whether you need to support legacy EDI alongside newer XML mandates. The vendor directory on this site lets you filter by country coverage and supported standards to find a match.

What other business documents are exchanged electronically?

E-invoicing is one part of a broader move towards fully electronic document exchange. Purchase orders, credit notes, debit notes, and advance shipping notices all follow similar structured-data principles, and many of the same standards (UBL, EDIFACT) define message types for each of them.

In a mature setup, the entire procure-to-pay cycle runs electronically: the buyer sends a purchase order, the supplier confirms it, ships the goods with a digital delivery note, issues an e-invoice, and receives an electronic payment advice. EDI has served this model for decades in retail and automotive; newer networks like Peppol are now opening it up to smaller organisations.