This guide provides an in-depth look at C.A.R's purchase agreement with step-by-step information about how to complete the RPA form. A California motor vehicle bill of sale is part of the vehicle registration process.Use a free template to write your own bill of sale. The AIR CRE Contract Library contains 63 forms needed to cover a commercial transaction. You will need the new owner's name and address. CAR (California Association of Realtors) residential purchase and sale agreements are widely used in real estate transactions throughout California. Below, we've outlined the steps and forms required for how to sell a car in the state of California so you can sell your car quickly for the most cash. My main focus is to show you car forms and how to get into that system and how to create a transaction.