Many people become landlords without planning to, or even knowing it. If you let someone move into your house, even with no lease, and no rent being paid, they become tenants because they are living there. Minnesota law defines a tenant as anyone residing in a place, with or without rent payment, and with or without a lease. When someone is a tenant they cannot just be made to leave if they do not want to, you have to give them notice to vacate, and can only evict if they still do not vacate. It is important that the notice to vacate be proper, in most cases a full month plus a day, though in some cases 90 days is required. When they do not vacate by the deadline you can evict, this means filing the eviction in court, getting it served on the tenants in time, and handling the eviction hearing. Watch out, many judges will do what they can to stop an eviction, if you make any mistake as a landlord your eviction will be denied.
Be careful who you let move into your house, and even more careful if you need to get them out.