What is on a bill of sale for a car in massachusetts? A bill of sale adds protection for the seller, providing supporting documentation for release of liability, and the buyer by acting as a receipt and proof of purchase. In addition to the standard details required for the sale of a vehicle, this document also includes a section for states requiring notarization for vehicle transfers. Whether you're selling a car, truck, motorcycle, or rv, this template provides a structured format to record key details of the sale. All forms available in word format.