Your "bill of sale".
The title to be changed must contain owner information that matches the owner information on the current vehicle registration. You must complete a registration application form (form #VD-119) providing an updated vehicle odometer reading and updated owner information. Each individual currently listed on the title must sign on the back of the title (as "sellers") and fill in the name of the "buyer(s)". If there are two owners you must indicate the relationship of the two owners.
See types of vehicle ownership for more information.