When is an invoice really legal? (and why a pdf is not an e-invoice)

Invoicing seems simple. You deliver something, send an invoice, and expect payment. Yet every invoice is subject to legal requirements that determine whether the invoice is legally valid. These requirements are there for a reason. They ensure that it is clear what has been delivered on what terms and how it should be processed for tax purposes. Without that basis, an invoice loses its value in the administration.

The basis of the transaction

In essence, an invoice is a document that records a payment obligation from a customer to a supplier. This is not just about the amount, but mainly about the justification for it. The invoice lines indicate what goods or services have been delivered, in what quantities and at what prices. Thus, the invoice is a specification of what has been delivered.

Legal requirements for clarity

The law's requirements for an invoice ensure that the invoice is complete, verifiable and traceable. In practice, this means that an invoice must always provide insight into who the parties involved are, what has been delivered and how the price is structured. In addition, the invoice must be unambiguously identifiable and consistent with the underlying delivery or performance.

The requirements apply to all invoices no matter how you send them: on paper or digitally, such as in a PDF.

A pdf is not an e-invoice

In many organizations, a digital invoice is still equated with a PDF. But that's wrong. A pdf is only a visual representation of an invoice. The information is therefore readable by humans, but not suitable for automatic processing by systems. As a result, manual processing remains necessary and creates room for errors.

An e-invoice is an invoice that is created, sent and received in a structured electronic form that enables automatic processing. This means that the invoice is immediately processed as data. Systems automatically recognize the content, without manual input.

From document to data stream

E-invoicing changes invoicing from an administrative action to an automated process. Manual checking and processing is no longer necessary; an e-invoice is immediately read and processed in systems. This ensures fewer errors, faster processing and more control over the administration.

Get a grip on your process

Legal requirements are the basis, but in practice it's about more than just complying with rules. An invoice must not only be correct on paper, but also fit into a process that is reliable, verifiable and efficient. This is precisely where e-invoicing makes a difference, as it brings structure to the way data is captured, exchanged and processed.

A legally valid invoice provides clarity, completeness and reliability. E-invoicing builds on that, but adds an extra dimension: structure and automatic processing. Thus, invoicing shifts from a document to an integral part of your business process. And that is exactly where the difference between just invoicing and getting a grip on your administration arises.

Checklist: is your invoice satisfactory?

Legal requirements (always required):

Invoice date
Unique invoice number
Name and address of supplier
Name and address of customer
VAT number supplier
(If applicable) customer's VAT number
Description of goods/services
Quantity
Price (excluding VAT)
VAT rate
VAT amount
Total amount
Delivery date (if different)
Authenticity of origin secured
Integrity of content ensured
Readable and reproducible
Traceable to delivery

Additional requirements in e-invoicing

Structured data (e.g., XML/UBL)
Automatic processing possible
Data preservation (not converting to paper or pdf)
Proof of authenticity
Proof of integrity
Exchange through a controlled digital route
Guarantee of readability and traceability
Legal archiving