I hve lived with my friend who is on the lease now for almost a year there are no signed documents for me being here but I have had my mail sent here for almost a year.Does that make me a legal tenant and do they still have to follow the laws of eviction?

As long as you pay rent you are a legal month-to-month tenant. Where your mail is sent doesn't matter. If they want you out they have to follow the laws of eviction for your state.