A motor vehicle bill of sale is between a buyer and a seller of a car, truck, or motorcycle. It is signed as the last step in the sales process.Access bill of sale form templates and learn how to transfer ownership of vehicles, boats, firearms, and other high-value personal items in Washington. If this was a gift, indicate relationship: (e.g. Parent, spouse, friend, etc.) SELLER INFORMATION. Access bill of sale form templates and learn how to transfer ownership of vehicles, boats, firearms, and other high-value personal items in Washington. Free Power of Attorney. Answer a few simple questions. Often combined with a signed title, the document summarizes the intricacies of the deal.