Eviction or other possible way?

My Girlfriend is living in Tampa Florida with her grandma in a house my girlfrind owns. Her grandma is terrorizing her for a long time now and she finally brought up the courage that she wants to kick her out. The question is would she need an eviction for that or can this happen on an oral agreement. There is no rent contract, her grandma is just living there with my girlfriend pretty much on her behalf and it is proven to be definetely my girlfriends house.