Your first real invoice in the KSeF Taxpayer App

You can issue an invoice in KSeF for free, without any software. All you need is a browser and a login, for example Profil Zaufany (the Polish trusted profile), in the KSeF 2.0 Taxpayer App at ap.ksef.mf.gov.pl. The app issues invoices online only, so you need an internet connection at the moment you send.

Below is the whole process, from login to the KSeF number and the UPO.

KSeF Taxpayer App (Ministry of Finance)

Who this is for

The Taxpayer App suits you if you issue a few invoices a month and have no invoicing software. For example, a VAT-exempt hairdresser who issues an invoice when a business client asks for one.

If you issue invoices in batches, software integrated with KSeF is a better fit. Typing everything by hand gets tiring quickly.

A VAT-exempt taxpayer issues an invoice only on the buyer's request (with the buyer's NIP, if it has one), made within 3 months of the end of the month in which the goods were delivered or the service was performed. They issue it in KSeF from 1 April 2026, or from 1 January 2027 if their sales do not exceed PLN 10,000. This is described in the KSeF 2.0 handbook, part II (edition of 6 August 2026).

What to prepare

A login method. Via login.gov.pl: Profil Zaufany, the mObywatel app, online banking or an e-ID card. For a sole trader, access works right away with Profil Zaufany or a qualified signature.
The login context. This is the NIP (tax ID) of the business you issue the invoice for. You enter it after choosing the login method.
The buyer's details. Name, address and NIP of the company that buys.
The line items. Name of the service or goods, quantity, price and VAT rate.

KSeF 2.0 Taxpayer App user manual (Ministry of Finance)

Step by step

1. Log in and choose the context

Go to ap.ksef.mf.gov.pl, choose a login method. Then pick the NIP identifier, enter your company's number and click "Przejdź dalej" (Continue). If you log in through login.gov.pl, you are redirected to its site, where you confirm your identity. Taxpayer Application manual, p. 14

2. Choose "Wystaw fakturę VAT"

In the side menu choose "Wystaw fakturę VAT" (Issue a VAT invoice). The app asks which form to use. For an ordinary domestic sale pick the short mode ("tryb skrócony"): it has the most common fields and fewer chances for mistakes. The extended mode is for less typical invoices.

3. Fill in the invoice data

In short mode you fill in, in turn:

Invoice number. You assign it yourself, following your own numbering.
Delivery or service date. The issue date fills in automatically and cannot be changed.
Payment due date and method (optional): cash, card or bank transfer, with an account number.
Net or gross prices. You choose which prices the invoice uses. The default currency is PLN.
Seller and buyer. Type the details by hand or fetch them by NIP with the "Pobierz dane" (Fetch data) button.
Line items. Name, quantity, unit, price and a VAT rate picked from a list.

If you sell with a VAT exemption, tick the exemption annotation and enter the provision you rely on. Which one to use is a question for your accountant, so we do not suggest one here.

Before sending, use the "Pozostałe akcje" (Other actions) button and the "Podgląd" (Preview) option to check how the invoice looks.

A sent invoice cannot be edited, cancelled or deleted. Check the buyer's NIP and the amounts before you click send.

4. Send to KSeF

Click "Wyślij do KSeF" (Send to KSeF). The system checks the document and, if everything is in order, passes it on to KSeF.

5. Save the KSeF number

After sending you will see the KSeF number, the unique identifier of the invoice. The "Kopiuj" (Copy) button copies it to the clipboard. You can also find the invoice later on the invoice list.

6. Download the UPO

The UPO (Urzędowe Poświadczenie Odbioru, the official confirmation of receipt) is KSeF's confirmation that the invoice arrived. Open "Historia sesji" (Session history), end the session and, in the sending details, choose "Pobierz UPO zbiorcze" (Download collective UPO) as XML or PDF. You can download the UPO for a single invoice from the invoice's context menu in the "Szczegóły wysyłki" (sending details) table under "Historia sesji". Taxpayer Application manual, pp. 125-126

KSeF 2.0 Taxpayer App user manual (Ministry of Finance)

How to give the invoice to your client

A buyer with a Polish NIP receives the invoice in their own KSeF. You do not need to send it by any other means.

It is different for the buyers listed in Article 106gb(4) of the VAT Act: when the place of supply is abroad, the buyer has no seat or fixed establishment in Poland (or its Polish establishment does not take part in the transaction), is exempt under Article 113a, has no tax identification number, or is a private individual outside business. Then you make the invoice available in a way agreed with them. The Ministry of Finance notes that the Act names no specific method and no form for the agreement. So you can send a visualisation, for example by email, but an invoice made available outside KSeF must carry a QR code (Article 106gb(5)(1)). KSeF 2.0 Manual, part II, pp. 23 and 82

You download an invoice from the invoice list by choosing a file format. A visualisation may also be in another language, as long as, once translated, it matches the data in the XML file.

Ministry of Finance FAQ (questions 16 and 25)

A mistake on the invoice

You cannot fix an error by editing. A sent invoice is corrected only with a corrective invoice. We described how in a separate article on corrections in KSeF.

The "Wystaw podobną fakturę" (Issue a similar invoice) option also helps: it opens a form filled with the data of the earlier invoice, which you can edit.

Limits of the app

Online only. The Taxpayer App does not issue offline invoices. When it is down, you have to wait or use another tool.
Manual work. You type every invoice yourself. For many documents, software integrated with KSeF is better.
Outages. The Ministry of Finance publishes outage notices on its technical notices page. One of them, dated 25 September 2026, concerned the production version of the Taxpayer App.

You can also issue an invoice in the KSeF mobile app. According to the Ministry's manual, it issues basic invoices and their corrections for domestic transactions in PLN, and corrections only for invoices issued in the same mobile app.

KSeF mobile app (Ministry of Finance)

What comes next

The PLN 10,000 monthly limit, which today exempts the smallest businesses from KSeF, applies until 31 December 2026 (Article 145m of the VAT Act). From 1 January 2027 KSeF covers everyone. VAT-exempt taxpayers follow the same stages. Penalties will be imposed only for violations from 1 January 2027, and for 2026 the Ministry does not impose sanctions for KSeF errors. More on the limit: The PLN 10,000 limit in KSeF.

Want to practise first?

Before you send a real invoice, you can rehearse the whole process in the test environment. We covered it in the guide KSeF test invoice: try it before you go live.

FAQ

Can I issue an invoice offline in the Taxpayer App?

No. In the KSeF 2.0 Taxpayer App you issue online invoices only.

Can I fix an invoice already sent to KSeF?

No. It cannot be edited, cancelled or deleted. Errors are fixed with a corrective invoice.

How long is an invoice kept in KSeF?

Structured invoices are stored in KSeF for 10 years, counted from the end of the year in which they were issued.