1 If you're financing your purchase ; 3 The actual vehicle purchase agreement ; 4 Buyer's trade in certification ; 5 Warranty disclaimer and documentary fee notice. Find out what documents you will need to provide proof of sale and ownership if you are buying, selling, or gifting a vehicle.You'll need to sign the car purchase agreement (or dealer bill of sale), the title, an odometer statement, and sometimes a damage disclosure statement. Use this car purchase agreement template to customize the financing information for your car along with other required details. Clearly print or type all information, except signatures. 1. Enter the buyer's name and contact information. 2. Odometer Declaration.