Before you arrive in Finland you must have a visa. You have hopefully done the visa application in your home country, and you already have it when you arrive. Without a valid visa you can’t arrive in Finland.
If you come to Finland form outside of EU for more than 90 days, you must apply for a residence permit. You need to apply for your residence permit personally. If you are a citizen of an EU member state, Iceland, Liechtenstein, Norway, or Switzerland, you don’t need visa or residence permit for Finland, but you must register your right of residence in Finland. Be aware with your residence permit. If your first residence permit is going to expire but you want to stay in Finland, apply for an extended permit.
The Finnish Immigration Service is a decision-making organization in matters related to immigration, asylum, refugee status and citizenship and maintains the reception system. The agency implements the Finnish immigration policy and promotes controlled immigration, good administration, and human and basic rights. The Finnish Immigration Service provides specialist and information services in support of political decision-
making and for national and international cooperation. The Finnish Immigration Service participates as a specialist in the discussion about immigration.
Applying a first residence permit: https://migri.fi/en/first-residence-permit
Extended residence permit: https://migri.fi/en/extended-permit
In Finland the police can issue you with a foreigner’s identity card if you have been identified and your identity has been reliably verified. Your identity can be verified from a document that proves your identity. If you so not have such a document, your fingerprints can be compared to the fingerprints stored on your residence permit card or residence card.
Other requirements that must be done:
You can use a foreigner’s identity card to prove your identity in Finland. You can use it for example when opening a bank account in Finland. However, you can’t use it as a travel document when travelling abroad.
Apply for an identity card here:
https://poliisi.fi/en/identity-card