When you log in to MyTax, your tax-related letters will change from paper to electronic form automatically. Read more about the changes.
If you are the project supervisor or main contractor at a shared construction site, you must file a report on all employees working at the site to the Tax Administration.
If the site has no appointed project supervisor or main contractor, the party commissioning the construction is responsible for reporting.
Choose your filing method
If you are submitting large batches of data, use Ilmoitin.fi.
Instructions for reporting – data format specification for employee details (VSTYONTE)
If you cannot file online, you can use the paper form. You can find the return address on the form. If you are filing details on an employee-leasing company and leased employees, also file Form 3721e. If you are filing details on the construction site’s or agreement’s employer or employees, also file Form 3722e.
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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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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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Page last updated 6/16/2026