In order to have an fi-domain name, you need a registrar. This search tool allows you to find easily all registrars that have been registered with Traficom. They register fi-domain names on your behalf and assist you in any domain name issues.
Usually registrars also provide optional services related to your domain name, such as email, web hosting and name servers.
(https://registry.domain.fi/search/en/app/registrars)