When you log in to MyTax, your tax-related letters will change from paper to electronic form automatically. Read more about the changes.
Submit the information in MyTax if possible. If you cannot use MyTax, you can use a paper form or authorise another person to act on your behalf.
You can apply for a car tax refund based on disability
- in advance, before purchasing the vehicle, or
- after the purchase, within six months from the date when the vehicle was first registered.
Choose your filing method
Read the instructions how to request a refund in MyTax (only in Finnish of Swedish, link to Finnish)
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