Advice of delivery
The Finnish Immigration Service sends some of its decisions in paper form with advice of delivery.
This means that you must prove your identity in order to collect the letter from the post office.
See the identity documents that post offices accept on the Posti website.
If you do not have an identity document accepted by the post office, you can give a written authorisation to a person who has one.
More information on written authorisations can be found on Posti’s website (in Finnish and in Swedish) where you can also fill out an authorisation form (power of attorney).