DVV and the personal identity code
The henkilotunnus is the 11-character code every Finnish system keys on. Most residence permit holders now receive it automatically with the permit decision; if not, you register in person at a DVV service point with your passport, permit and address. Separately, staying at least a year lets DVV record an official municipality of residence (kotikunta), which unlocks municipal services, from healthcare to Finnish courses. Bring your rental agreement and, for families, legalised marriage and birth certificates to get everyone registered in one visit.