To perform a wedding ceremony in Minnesota, you must register with a Minnesota county prior to the ceremony. No credentials are required to register with the county. (MN State Statute 517.04)
Ministers of any religious denomination, before they are authorized to solemnize a marriage, shall file a copy of their credential of license or ordination or, if their religious denomination does not issue credentials, authority from the minister’s spiritual assembly, with the local registrar of a county in this state. (MN State Statute 517.05)