For the seller's security, a contract for the payments should be drafted and both you and the seller should have a notarized copy. Once the agreement has been signed by both of you then the seller should cancel the insurance coverage and registration on the vehicle as well as transfer the title to your name. At the time that you take possession of the vehicle, it will be up to you to register and insure
the vehicle before driving on a public roadway. This will essentially transfer ownership and any legal liability to you and the owner cannot be held liable for anything you might do with the vehicle.