Notification of move is useful in many ways

The notification of move can be made at the earliest one month in advance. However you must take care of that the notification has been received by the Digital and Population Data Services Agency within a week of your move at the latest.

Make your notification well in advance before your move to make sure your post will immediately be delivered to the right address. Up-to-date address information will speed up handling of matters at your home municipality and wellbeing services county, your taxes will be directed to the correct municipality and at elections you can vote at the nearest polling station.
 

By submitting a notification of move you can notify your new address simultaneously to the national Population Information System maintained by the Digital and Population Data Services Agency as well as to the register of Posti.

Your address details will automatically be forwarded from the Population Information System to many public authorities including municipalities, wellbeing services counties, the Finnish Transport and Communications Agency's (Traficom) Vehicular and Driver Data Register, the Social Insurance Institution of Finland (Kela), the Finnish Tax Administration and the Finnish Defence Forces. In addition, many pension institutions, banks and insurance companies receive your new address details without you having to notify them separately. Also many other companies, such as publishing houses and energy companies, as well as associations receive your new address details, unless you have forbidden the disclosure of your personal information.

Also Posti automatically forwards address information to the companies who have made contract with Posti.

Yes. The Finnish authorities need to be told about any change of address, even when a Finnish citizen moves from one address to another abroad. This applies both when moving within one foreign country or from one foreign country to another. You may notify the Digital and Population Data Services Agency of your address abroad. You may also notify it in your country of residence via the local Finnish consulate, etc.