Nationals who are required to hold a visa must always be in possession of one when entering the Schengen area.
Foreign nationals who need a Schengen visa for travel to Finland are requested to apply for it at the nearest Finnish mission. If you are a resident in the Republic of Ireland you should apply in the Embassy of Finland in Dublin. In countries where Finland does not have a mission, another Schengen country can represent Finland in visa issues.
If you intend to stay in Finland for longer periods e.g. studying or working (more than 90 days within any 180 day period) you will need a residence permit. There are exceptions to this rule for the citizens of other Nordic countries, EU and EEA countries.
As a rule, the first residence permit must be applied for at a Finnish embassy in the applicant's native country or in your country of residence. The embassy will provide further information on the application process. The process itself and the final decision will be given by the Finnish Immigration Services.
Please see the visa requirements and travel documents accepted by Finland - listed by country - via this link :