When you log in to MyTax, your tax-related letters will change from paper to electronic form automatically. Read more about the changes.
Use Form 70 to claim credit for foreign taxes in Finnish income taxation. The form must be filled in when the company has paid foreign taxes during the tax year, and in cases where it has not been possible to credit foreign taxes in the previous year.
Choose your filing method
Submit the information in MyTax as part of the tax return.
Need instructions for filling in the fields? If so, you can read the instructions for completing the paper form.
You can also give the information electronically by uploading a file in the Ilmoitin.fi service.
If you use Ilmoitin.fi, send us the attachment forms together with the main tax return form.
Do not send any paper forms if you use an online channel for filing the company’s tax return.
Guidance for income tax returns as software files — specifications of data formats
Self-employed operators of a trade or business, general partnerships, and limited partnerships need to send the paper form enclosed with their tax return.
Limited companies and other corporate entities need to send paper forms to:
Finnish Tax Administration
OCR Service of corporate taxpayers’ returns
PO Box 200, 00052 Vero
Download the form
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The online authorisation mandate
You can use the Suomi.fi Authorization to enable you to deal with taxes for another person – including legal persons, companies, other entities – through e-services, over the telephone, or by visiting a service point on their behalf.
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Huomio osio alkaa
Letters of authorisation on paper
You can receive a letter of authorisation written in the name of a company, to manage a single tax-related issue. If you – either personally or for an organisation that had been authorised – submit tax-related information on paper, a copy of the letter of authorisation has to be enclosed. A letter of authorisation does not provide access to MyTax.
Power of attorney for managing the taxes of a company (3804)
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Key terms:
Page last updated 3/12/2026