If there is no lease and they get mail at that address do you have to file a court ordered eviction?

Are you asking if a tenant without a lease has to be evicted by State Law? Yes, if they won't move willingly.

Generally if a person gets mail, they are a resident and a resident needs to be removed by going through the proper eviction process.

I agree with Judy and Scott but you could give us some additional details. Are you the owner or the lessee or the person not on the lease? Getting mail at an address is not reqiured to establish residency. Once a person is a resident then you'd have to follow your states eviction process, where do you live?