Summary of the procedure

How should an accounting firm and clients currently invoicing in Excel move to e-invoice?

Short answer

Treat the change as two coordinated workflows: one for the accounting firm and one for each client, covering both issued and received invoices. Select the delivery-service arrangement, agree responsibilities and access, define how valid XML is created from the client’s source data, route issued and received documents, and test their import and review before accounting entries are posted.

1. Choice of solution

Each client decides for himself

An accounting firm can help by authorization; common provider is not a legal requirement.

2. – 3. Informing and decision of the client

Same or different provider

The Excel client chooses a postman according to his needs.

4. – 5. Data flow

Documents issued and received

XML generation, sending, downloading and forwarding to the accountant.

6. Import and control

In the accounting system

The error is not corrected by rewriting the sent XML, but by a subsequent correction document according to the nature of the change.

Conclusion

The transition combines provider selection, client decisions, defined flows for issued and received documents, and controlled import into the accounting system before posting.

Sources

  • Law no. 222/2004 Z. z. Coll. on VAT, § 71 and § 85o (as amended by Act No. 385/2025 Z. z. Coll.)

Slov-Lex: Act No. 385/2025 Z. z. Coll. · FAQ of the Financial Administration of the Slovak Republic on e-invoice

Not legal advice.