The end of paper invoices on business trips. The introduction of mandatory e-invoicing through the National e-Invoicing System (KSeF) will significantly impact the way employee expenses are handled. Until now, employees typically returned from business trips with a full set of invoices documenting fuel, accommodation or transport costs. Under the new rules, this model will change.

Invoices go to the system, not to employees

Once KSeF becomes mandatory, invoices documenting employee business expenses will be issued as structured e-invoices and delivered directly to the employer via the system. In many cases, employees may not receive a paper invoice or even a visual version at the time of purchase. Instead, the invoice will appear in KSeF together with other purchase invoices assigned to the employer’s tax ID.

This creates a key challenge: how to identify which invoice relates to which employee and which expense.

New processes instead of manual work

To avoid confusion, companies need to implement procedures that allow them to:

• identify employee-related invoices in KSeF,
• assign them to the correct employee,
• describe and approve expenses internally.

These procedures should be flexible, as employees may receive different types of transaction confirmations from suppliers. It is therefore crucial that invoices include additional data enabling employee identification — such as name, email address, employee ID, or vehicle registration number in the case of fuel purchases.

If an employee receives another document confirming the transaction, it should contain information that allows it to be linked to the invoice available in KSeF, including the invoice date, number and amounts.

Tools for identifying employee expenses in KSeF

The FA(3) e-invoice structure offers several options that can support the identification of employee-related expenses:

1. Internal identifier (IDWew)

Employers can generate internal identifiers for employees and use the IDWew field in the Podmiot3 section of the invoice. This allows invoices to be clearly assigned to specific individuals and access rights to be granted to accounting staff or employees themselves.

2. Employee data in Podmiot3

Alternatively, the Podmiot3 section may include employee details and their role, without using an internal identifier. This simpler approach can also be effective.

3. Additional description field

The FA(3) structure includes a DodatkowyOpis (AdditionalDescription) field where extra information can be added, such as employee details and a note that the invoice relates to an employee expense.

Tailored solutions for each organization

These are only examples. Employers are free to design their own invoice identification and access processes based on their organizational structure, number of employees and internal systems.

One thing is certain: KSeF will fundamentally change how employee expenses are settled — and early preparation will make all the difference.