When you log in to MyTax, your tax-related letters will change from paper to electronic form automatically. Read more about the changes.
Submit a declaration of use for an employee car registered abroad in MyTax if possible. If you cannot use MyTax, you can use a paper form or authorise another person to act on your behalf.
Submit a declaration of use for an employee car registered abroad before you start using the vehicle in Finland. This use is tax-exempt if all the following conditions are met
- you are a permanent resident of Finland
- your employer has a permanent establishment in a country other than Finland
- the company car is owned or controlled by your employer and registered abroad
- the vehicle is used less in Finland than abroad.
Choose you filing method
If the Tax Administration does not have your address, for example if you live abroad, also submit the Notification of mailing address.
Download the form
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The online authorisation mandate
You can use the feature called “Suomi.fi Authorization” to enable you to deal with another person’s taxes through e-services, over the telephone, or by visiting a service point on their behalf.
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Letters of authorisation on paper
You can receive a letter of authorisation from the other person. It will enable you to deal with that person’s taxes on the telephone, by visiting a service point on their behalf, or by submitting information on paper tax forms. To have a letter of authorisation (often called a ‘power of attorney’) does not provide access to MyTax.
Letter of authorisation for tax representation of individual taxpayers
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When is there no need for an authorisation mandate?
The following circumstances are examples of when you can deal with someone else’s taxes with no authorisation.
You have child younger than 18 and you handle the child’s taxes
You are automatically authorised to access MyTax for the child, without an authorisation. Log in to MyTax and select “Act on behalf of someone else”.
Read more about this subject on Suomi.fi.
You are a guardian
You do not need a Suomi.fi authorisation when your continuing power of attorney for being a guardian is officially confirmed, or when you are registered as a private guardian. Log in to MyTax and select “Act on behalf of someone else”.
Note: If you are a public guardian, in other words, a public official employed by a public guardianship office, you can only use paper forms.
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Page last updated 1/1/2026