How to Issue, Submit & Correct Invoices in Poland
A practical guide for foreign entrepreneurs, no accountancy jargon, no confusing Polish-only instructions. Just what you need to stay compliant from 1 April 2026.
Mandatory from 1 April 2026
Reading time: ~10 min
What is KSeF and who must use it?
KSeF (Krajowy System e-Faktur) is Poland’s national e-invoicing platform, operated by the Polish tax authority. Starting 1 April 2026, all businesses registered for VAT in Poland, including foreign companies operating through a Polish entity or VAT registration, must issue invoices through this system.
Large taxpayers (annual turnover above PLN 200 million) have been mandatory since 1 February 2026. All other VAT-registered businesses must comply from 1 April 2026. If your monthly invoices total below PLN 10,000, you may temporarily continue issuing traditional invoices until the end of 2026.
The key thing to understand is that KSeF invoices are not PDF files. They are structured XML documents. Once submitted, each invoice receives a unique KSeF identification number, only then is the invoice considered legally issued.
Does KSeF apply to your company?
As a foreign entrepreneur, KSeF applies to you if:
- Your company has a registered seat or fixed establishment in Poland, or
- You are registered for VAT in Poland (even without a physical presence), and
- You issue B2B invoices with Polish VAT (not B2C, not OSS/IOSS).
If you only have a Polish VAT number but no physical establishment, your obligation may be limited, this depends on your specific situation. When in doubt, consult a local compliance adviser.
Which signature do you need?
To access KSeF directly, whether to submit invoices, grant permissions, or manage settings, you must authenticate yourself. There are three methods available, and the right choice depends on your situation as a foreign entrepreneur.
Although many accountants offer to register your KSeF account and manage it entirely in-house, we recommend that the company owner registers the KSeF account themselves and remains the administrator. You then grant access to your accountant or other relevant personnel, keeping full control and visibility over your own invoicing. Complium can help you open the KSeF account and advise you on how to correctly grant access to your accountant.
| Method | Who it’s for | How to get it | Suitable for foreigners? |
|---|---|---|---|
| Qualified Electronic Signature (QES) | Individuals and companies signing on behalf of a legal entity | Purchased from certified Polish or EU providers (e.g. Certum, EuroCert). Requires identity verification, can often be done remotely. | Recommended |
| Qualified Electronic Seal | Companies (legal entities), the seal is assigned to the company, not a person | Purchased from certified providers. Useful for automated, high-volume invoicing via integrated software. | Yes, for companies |
| Trusted Profile (Profil Zaufany) | Anyone with a Polish PESEL number, including EU residents who have registered a company in Poland | Created free of charge via profil.zaufany.pl or via eIDAS for EU residents. Requires a PESEL number, which every foreign company founder in Poland should already have. | Recommended |
If you are setting up a company in Poland as a foreigner, obtaining a PESEL number is the first thing you should do, before registering the company. You need it for the UBO registry, for signing company documents, and for accessing the Trusted Profile. With a PESEL in hand, the Trusted Profile is free and straightforward to set up, and gives you full access to KSeF and Polish government e-services. The order is: PESEL → Trusted Profile → KSeF access.
Where to get a Qualified Electronic Signature
If for any reason you cannot obtain a Trusted Profile, a Qualified Electronic Signature (QES) is the alternative. Contact Complium Poland to get a quote and assistance with obtaining one.
How to create your KSeF account
Before you can use KSeF, you need to open your company’s account with the tax office. This is done by submitting the ZAW-FA form, the official notification that registers your company in the KSeF system and establishes who the administrator is. The tax office processes the form and opens your access. Only after that can you log in to KSeF.
How you submit the ZAW-FA depends on what authentication method you have:
If you have a Trusted Profile
With a Trusted Profile you can submit the ZAW-FA either as a paper form delivered to your local tax office, or electronically through the e-tax office portal (e-Urząd Skarbowy). However, to access the e-tax office portal, you first need to submit a separate form, the ZAP-3, which grants you access to that system. This adds an extra step that many foreign entrepreneurs are not aware of.
In plain terms: the ZAP-3 opens your access to the e-tax office, and the ZAW-FA registers your company in KSeF. Both are needed, and both can be submitted on paper if you do not yet have online access set up.
Complium Poland can prepare both the ZAP-3 and ZAW-FA forms on your behalf and submit them to the tax office. Once the account is open, we will guide you through completing the setup and logging in as the administrator for the first time.
If you have a Qualified Electronic Signature (QES)
With a QES you can submit both the ZAP-3 and ZAW-FA forms entirely online, without needing to visit a tax office or send paper documents. This is the most straightforward path if you already have a QES in place.
Complium Poland can assist you in completing and submitting both forms online using your QES, ensuring everything is filled in correctly and sent to the right authority.
How to grant access to your accountant
Once your KSeF account is open and you are the administrator, you can authorise your accountant, compliance provider, or any other relevant person to act within KSeF on your behalf. You remain in control, you decide what level of access each person gets, and you can revoke it at any time.
Access is granted through the ZAW-FA form as well, by listing the person you wish to authorise and specifying their permission level: full access (invoice issuance and management) or read-only access.
Not sure which access level to grant or how to complete the authorisation correctly? Complium Poland can guide you through the process and make sure your accountant or provider is set up with exactly the right permissions.
How to submit an invoice manually in KSeF
If your accountant handles invoicing through integrated software, they will submit invoices automatically once connected via token. But if you need to issue an invoice yourself, the Polish Ministry of Finance provides a free tool for this: the KSeF Taxpayer Application, available at ksef.podatki.gov.pl. It is a web-based form where you can fill in all invoice fields and submit directly, no XML knowledge required.
From April 2026, direct authentication in KSeF may require the use of a KSeF Certificate or Qualified Electronic Signature, depending on the access method used. The KSeF Certificate is available from the Certificates and Authorisations Module (MCU) on the KSeF portal. Your accountant or Complium can help you obtain this.
Step-by-step: issuing an invoice in the KSeF Taxpayer Application
Go to ksef.podatki.gov.pl and log in using your KSeF Certificate or Qualified Electronic Signature. Once logged in, you will see your company dashboard with issued and received invoices.
Select the option to create a new invoice. The form will open with all required fields. The interface is in Polish, if needed, use your browser’s built-in translation to English.
Your company’s name, address, and NIP (tax number) go here. These may be pre-filled based on your login, verify they are correct before continuing.
Enter your client’s company name, address, and NIP. This is critical, the NIP must be exact, as the system uses it to deliver the invoice to the buyer’s KSeF account. A wrong NIP means the buyer cannot see the invoice.
Enter each service or product: name, quantity, unit price, VAT rate, and net/gross amounts. The system will calculate VAT totals automatically. Add as many lines as needed.
Enter the invoice issue date (P_1 field), this must be the date you are submitting, as KSeF treats the submission date as the legal issue date. Add the payment due date and bank account number if required.
Check all details carefully before submitting, corrections require a formal corrective invoice (see Section 5). When ready, click submit. KSeF will validate the data within seconds.
If the invoice passes validation, KSeF assigns a unique KSeF number to it. The invoice is now legally issued. Your buyer can see it automatically in their own KSeF account, there is no need to send a PDF by email.
From August 2026, the KSeF number must be included in bank transfer references when requesting payment. Keep a record of it for every invoice issued.
How to correct or credit an invoice
Mistakes happen. If you need to change something on an issued KSeF invoice, a wrong amount, incorrect buyer details, a service that was cancelled, you must issue a formal corrective invoice (faktura korygująca) through KSeF.
The old system of corrective notes (nota korygująca) issued by the buyer is no longer used from 2026. All corrections must now be made by the original invoice issuer through KSeF as a corrective invoice.
Two types of corrective invoice
Used when one or a few fields are wrong, for example, the VAT rate, a line item amount, or buyer details. The correction invoice references the original KSeF number and specifies only what changes.
Used to cancel an entire invoice, for example, if a service was not delivered. The corrective invoice brings the total to zero, effectively voiding the original.
Step-by-step: issuing a corrective invoice in the KSeF Taxpayer Application
Log in to the KSeF Taxpayer Application at ksef.podatki.gov.pl. Go to your list of issued invoices and find the invoice you need to correct. Note its KSeF number, you will need this to link the correction to the original.
Open the original invoice and choose the option to issue a correction. The system will pre-fill the original invoice data and automatically reference the original KSeF number, you do not need to enter it manually.
This field is required. Write a brief, clear description of why the correction is being made, for example: “Incorrect VAT rate applied” or “Service not provided, full credit.” Keep it factual.
For a partial correction, update only the incorrect fields, amount, VAT rate, buyer details, etc. Leave everything else unchanged. For a full credit (cancelling the entire invoice), set all amounts to zero.
Check the corrected data carefully, then submit. KSeF will validate and assign a new KSeF number to the corrective invoice. Your buyer will see it automatically in their own KSeF account.
For corrections that reduce the VAT amount, the adjustment applies in the period when the corrective invoice receives its KSeF number. For corrections that increase VAT, the adjustment applies to the period of the original invoice.
Although the buyer sees the corrective invoice in KSeF automatically, it is good practice to inform them, especially if the correction affects a payment amount or VAT they have already recorded.
Common mistakes and how to avoid them
Based on practical experience working with foreign clients operating in Poland, these are the most frequent issues that arise with KSeF compliance:
- Sending PDF invoices after the deadline. PDF invoices are no longer valid for B2B VAT transactions. Make sure your billing process is updated before 1 April 2026.
- Wrong NIP number on the invoice. The buyer’s NIP must be correct, the system validates it. A wrong NIP means the buyer cannot retrieve the invoice in their KSeF account, and the invoice may be invalid.
- Not having authentication set up in advance. Getting a QES or setting up the ZAW-FA authorisation takes days, not hours. Do not leave this until the last moment.
- Issuing a corrective note instead of a corrective invoice. Corrective notes are abolished from 2026. Any change to an invoice must go through KSeF as a formal corrective invoice.
- Missing the KSeF number on payment references. When requesting payment, you should now reference the KSeF invoice number, not just your own invoice number. This is increasingly expected by Polish companies.
- Attaching non-invoice documents to KSeF invoices. KSeF attachments introduced in 2026 are strictly for invoice-related data (e.g. detailed billing breakdowns). Do not attach contracts, marketing materials, or unrelated documents.
We help foreign entrepreneurs operating in Poland navigate KSeF compliance, from setting up authentication to managing invoices and corrections on your behalf.
