If you own and he is not also an owner of the property, you will have to evict him through the courts.
If you own the property together, you cannot evict him.
If you rent and he is on the lease, he can only be evicted by the LL *IF* he has violated the lease in any way.
If you rent and he is not on the lease nor has he been approved for residency by the LL, all of you are subject to eviction for a lease violation. You cannot allow someone to move in without the LL's prior written permission