E-Invoicing Explained: What It Is, How It Works and How to Prepare

For decades, "electronic invoicing" meant emailing a PDF. That saved postage, but the buyer still had to read the invoice and type its details into their system, or use OCR to extract them. True e-invoicing removes that step: the invoice travels as structured data from the seller's system directly into the buyer's, ready to be validated, matched and posted.

E-invoicing has moved from a nice-to-have to a legal requirement in a growing number of countries, driven mainly by governments seeking to close VAT gaps and digitize tax reporting. This guide explains what e-invoicing is, the main formats and networks, the different regulatory models, what mandates look like, how e-invoicing affects AP and AR processes, and how to prepare. Mandates and dates change frequently, so check official tax authority sources for the countries where you operate.

What counts as an e-invoice?

An e-invoice in the strict sense is an invoice issued, transmitted and received in a structured electronic format that allows automatic processing. The key word is structured: each piece of information (supplier tax ID, invoice number, line amount, tax rate) is a defined data element, not just text on a page.

Format	Example	Structured?	Counts as e-invoice in mandates?
Paper	Posted invoice	No	No
PDF or image by email	Invoice.pdf	No (needs OCR)	Generally no
Hybrid	PDF with embedded XML (Factur-X/ZUGFeRD)	Yes, in the XML part	Often yes, depending on country rules
Structured XML or JSON	UBL, CII, national formats	Yes	Yes, if the format is accepted
EDI messages	EDIFACT, ANSI X12 invoices	Yes	Sometimes, depending on rules

Under many mandates, a PDF will no longer satisfy the legal requirement for an invoice between businesses, even if it looks identical. Sending one where an e-invoice is required may mean the invoice is not valid for tax purposes, which can affect the buyer's right to reclaim VAT.

Benefits of e-invoicing

For buyers:

• No data entry or extraction; fewer errors.
• Faster matching and approval; automatic validation.
• Earlier visibility of liabilities.
• Lower risk of fake invoices when invoices come through authenticated channels.

For sellers:

• Faster delivery and confirmation of receipt.
• Fewer rejections due to missing information.
• Potentially faster payment.

For governments:

• Real-time or near-real-time visibility of transactions, helping to reduce VAT fraud and the VAT gap.

Standards and formats

EN 16931

The European standard EN 16931 defines a semantic data model for the core elements of an electronic invoice and specifies syntaxes that can carry it, notably UBL 2.1 and UN/CEFACT CII. EU public authorities must be able to receive e-invoices compliant with this standard under Directive 2014/55/EU. Many national formats are based on it.

UBL (Universal Business Language)

An XML standard from OASIS widely used for e-invoicing, including in the Peppol network.

CII (Cross Industry Invoice)

A UN/CEFACT XML syntax, also supported by EN 16931, used in some national formats.

Hybrid formats

Factur-X (France) and ZUGFeRD (Germany) combine a human-readable PDF with embedded XML data in a single file. They suit businesses whose customers have mixed capabilities.

National formats

Some countries use their own formats, such as XRechnung in Germany for public sector invoicing or FatturaPA in Italy, typically aligned with or mapped to the European standard.

EDI

Large companies have exchanged invoices via EDI (EDIFACT, ANSI X12) for decades, usually with major trading partners such as retailers and manufacturers. EDI is structured, but whether it satisfies a specific legal mandate depends on local rules.

Delivery models

Peppol and interoperability networks

Peppol is an international network and set of specifications for exchanging business documents. It uses a "four-corner" model: the seller (corner 1) sends through its access point provider (corner 2) to the buyer's access point (corner 3), which delivers to the buyer (corner 4). Participants are found through a directory using identifiers. Businesses connect once, through a certified access point provider or their accounting software, and can then exchange invoices with anyone on the network. Peppol is used for e-invoicing in many European countries and in places such as Australia, New Zealand, Singapore and Japan, in various roles.

Clearance (continuous transaction controls)

In clearance models, the invoice must be submitted to a tax authority platform, which validates it, and in some cases approves it, before or as it reaches the buyer. Italy's SdI is a well-known European example, used for business-to-business invoicing since 2019. Several Latin American countries, such as Mexico and Brazil, pioneered clearance systems; others, including Saudi Arabia and India (for businesses above certain turnover thresholds), have their own platforms.

Post-audit with reporting

Some systems let invoices flow directly between businesses but require transaction data to be reported to the tax authority in near real time or periodically. Hybrid models combine exchange networks with reporting.

E-invoicing and e-reporting

E-invoicing is often paired with e-reporting: sending transaction data to the tax authority for transactions that are not covered by the e-invoice exchange, such as sales to consumers, cross-border sales or payment data. In some countries, the same platform handles both. When assessing your obligations, check whether reporting requirements apply alongside invoicing ones, because they may affect sales that are not invoiced to businesses at all.

The European picture

Europe is moving quickly, with national mandates and an EU-level reform:

• Italy: mandatory B2B e-invoicing through SdI since 2019.
• Germany: since 1 January 2025 businesses must generally be able to receive structured e-invoices for domestic B2B transactions, with issuing obligations phased in over the following years.
• France: a phased mandate starting September 2026, beginning with the obligation to receive e-invoices and issuing obligations for larger companies, with smaller businesses following later.
• Belgium: B2B e-invoicing mandatory from January 2026, with Peppol as the main channel.
• Poland: the national KSeF system, with mandatory use phased in during 2026.
• EU-wide: the VAT in the Digital Age (ViDA) package, adopted in 2025, introduces e-invoicing and digital reporting for intra-EU business transactions from 2030 and makes it easier for member states to introduce domestic mandates.

Dates, thresholds and exemptions have shifted several times in some countries, so always verify against current official guidance.

Elsewhere in the world

• Latin America: Mexico (CFDI), Brazil (NF-e and related documents), Chile, Colombia and others have long-established clearance systems.
• Asia-Pacific: Australia, New Zealand and Singapore promote Peppol-based e-invoicing; India requires e-invoicing for GST-registered businesses above a turnover threshold; Malaysia is phasing in a national e-invoicing system.
• Middle East: Saudi Arabia's FATOORA programme is being rolled out in waves.
• United States: there is no federal e-invoicing mandate. Industry initiatives have developed exchange frameworks, and adoption is voluntary.
• United Kingdom: there is currently no general B2B mandate, though the government has consulted on promoting e-invoicing; public sector bodies may require it for their suppliers.

What an e-invoice contains

A structured e-invoice carries the same business information as a traditional invoice, but each element is tagged. Core elements in the European standard include:

Group	Examples of data elements
Invoice identification	Invoice number, issue date, invoice type code (invoice or credit note), currency
Process references	Purchase order reference, contract reference, preceding invoice reference for credit notes
Seller	Legal name, VAT identifier, address, electronic address
Buyer	Legal name, VAT identifier, address, electronic address, buyer reference
Delivery	Delivery date or period, delivery address
Payment	Due date, payment terms, payment means, IBAN or other account details
Allowances and charges	Discounts, surcharges, with tax categories
Totals	Sum of line amounts, total without tax, tax total, total with tax, amount due
Tax breakdown	Per tax category and rate: taxable amount and tax amount
Lines	Line ID, quantity, unit, net price, item name and identifiers, tax category, line amount

Because each element is defined, the receiving system can validate it automatically: is the VAT identifier in a valid format, do the line amounts add up, is the tax breakdown consistent? Validation rules published alongside the standards, often as Schematron rules, let software check invoices before they are sent.

Legal validity and archiving

In the EU, the VAT rules require that the authenticity of origin, the integrity of content and the legibility of an invoice be ensured from issue until the end of the storage period. Businesses can meet this through business controls that create a reliable audit trail between the invoice and the supply, through electronic signatures, or through EDI. Structured e-invoices exchanged via accredited networks or tax platforms typically make this easier to demonstrate.

For archiving:

• Keep the original structured file, not just a PDF rendering, where the rules require it.
• Store it for the statutory period, which varies by country.
• Ensure it can be retrieved and read throughout that period, including after software changes.
• In clearance countries, the tax authority's copy may also be the reference; know how to retrieve it.

Choosing an e-invoicing solution

Option	How it works	Suits
Built into accounting software	Software sends and receives via a partner access point	Small and medium businesses already using cloud accounting
ERP add-on or connector	ERP generates formats; connector handles transmission	Larger companies on ERP systems
Specialist e-invoicing service provider	Multi-country formats, networks and clearance connections	Companies trading in several mandate countries
Government portal	Manual entry or upload on a free public platform	Very low volumes where available

Questions to ask providers: which countries, formats and networks are supported; how mandates and format updates are kept current; how validation errors and rejections are handled; how archiving works; what it costs per invoice or per month; and how inbound e-invoices reach your AP workflow.

Worked example: a small supplier preparing for a mandate

A small engineering firm in a country introducing B2B e-invoicing issues about 80 invoices a month and receives about 150.

1. Check the timeline: the firm must be able to receive e-invoices from the first mandate date and issue them a year later.
2. Check software: its cloud accounting provider confirms it will support the required format through a partner access point, included in the subscription.
3. Register: the firm activates e-invoicing in the software, which registers its identifier in the network directory.
4. Update master data: it adds customers' tax numbers and electronic addresses, and corrects several outdated legal names.
5. Test: it exchanges test invoices with two large customers.
6. Receive: inbound e-invoices begin arriving as draft bills, with no extraction required; PDFs from small foreign suppliers still come by email.
7. Issue: from the issuing date, every sales invoice is sent as an e-invoice; the PDF copy is optional.

The total internal effort was a few days, mostly cleaning customer data. Firms that leave preparation to the last month often find that missing tax numbers and inconsistent customer records cause the most delay.

How e-invoicing changes accounts payable

With structured invoices, AP shifts further from data capture to validation and exceptions:

1. Invoices arrive as data in the AP system.
2. Validation checks run automatically: format, mandatory fields, arithmetic, tax.
3. Supplier and PO matching happens with exact data. See three-way matching.
4. Exceptions are handled as before, but extraction errors disappear.

AP teams will typically receive a mix of e-invoices and PDFs for years, especially from small or foreign suppliers. Invoice data extraction remains necessary for the PDF share, and it is wise to plan for both channels.

How e-invoicing changes accounts receivable

For sellers:

• Invoices must be generated in the required format and contain all mandatory fields.
• Customer identifiers (such as Peppol IDs or tax numbers) must be maintained in customer master data.
• Invoice rejection or acceptance messages may need to be handled.
• In clearance countries, invoices are not valid until accepted by the tax platform.

How to prepare: a practical plan

1. Map obligations: list the countries where you issue or receive invoices and check their current mandates, dates and thresholds.
2. Ask your software provider: does your accounting or ERP system support the required formats and networks, or do you need an e-invoicing service provider or access point?
3. Clean master data: tax numbers, legal names and addresses of customers and suppliers; add network identifiers.
4. Review invoice content: ensure invoices contain all mandatory fields, such as tax breakdowns and references.
5. Plan receiving: in many mandates, the obligation to receive comes before the obligation to issue.
6. Test with a few trading partners before deadlines.
7. Update processes: approval, archiving and handling of rejections.
8. Plan archiving: e-invoices must usually be stored in their original structured format for the legal retention period.

E-invoicing and bank reconciliation

E-invoicing streamlines invoices, but payments still flow through bank accounts. Reconciliation remains essential: confirming that each invoice was paid or received, once, at the right amount. Structured remittance information in payments, such as ISO 20022 messages, helps automatic matching. Where bank data is only available as PDF statements, a bank statement converter closes the gap, turning statements into data for reconciliation. See how to reconcile a bank statement.

Common misconceptions

• "We email PDFs, so we already do e-invoicing." Not under most mandates.
• "E-invoicing is only for large companies." Many mandates eventually cover all businesses, including small ones.
• "We only need to issue e-invoices." Several mandates require businesses to receive them first.
• "One format works everywhere." Countries differ in formats, networks and clearance requirements.
• "E-invoicing removes all AP work." It removes data capture, not approvals, exceptions or reconciliation.

Frequently asked questions

What is e-invoicing?

E-invoicing is the exchange of invoices in a structured electronic format, such as UBL or CII XML, directly between the seller's and buyer's systems, allowing automatic processing without manual data entry.

Is a PDF invoice an e-invoice?

Generally no. A PDF is a digital image of an invoice and needs to be read or extracted. Most e-invoicing mandates require structured data, although some accept hybrid formats where XML is embedded in a PDF.

What is Peppol?

Peppol is an international network and set of specifications for exchanging business documents, including invoices, using a four-corner model with certified access point providers. Once connected, a business can exchange e-invoices with any other Peppol participant.

Is e-invoicing mandatory?

In a growing number of countries, yes, at least for certain businesses or transaction types. Requirements, formats and timelines differ by country and change over time, so check the official guidance for each country where you operate.

What is the difference between clearance and post-audit e-invoicing?

In a clearance model, the invoice is submitted to a tax authority platform for validation before or as it reaches the buyer, and is not legally valid until cleared. In a post-audit model, invoices flow directly between businesses and the tax authority reviews records later, sometimes with periodic or real-time reporting.

Do small businesses need to prepare for e-invoicing?

Yes, in countries with mandates. Many accounting software providers are adding e-invoicing support, so the first step is to check what your software offers and when.

Summary

E-invoicing replaces PDF and paper invoices with structured data that flows between systems, often through networks like Peppol or tax authority platforms. It reduces manual work and errors, and governments increasingly require it. Map your obligations, check your software, clean master data and plan for a period where e-invoices and PDFs coexist.

Payments still need reconciling: StatementPilot turns PDF bank statements into structured data, the same way e-invoicing does for invoices.