First time buying rental - tenant contract question

[Brad Swearingen]

I am buying my first rental with a tenant already in the home.  He has no contract with the current owner and is just month to month with her.  When I take over ownership, do I ask tenant to sign a contract for 12 months? or do I just stay month to month?  How does he know my rules if he doesn't sign a contract? Can I give him some rules and not have him sign a contract?  What do you all do in this situation?