For more information, contact customer service at 360.902.3770. Forms are available online at dol.wa.An RV Bill of Sale is a legal document that serves as proof of the sale and transfer of ownership of a recreational vehicle (RV) from a seller to a buyer. Use this form to gather necessary information when you sell your vehicle or vessel. Access bill of sale form templates and learn how to transfer ownership of vehicles, boats, firearms, and other high-value personal items in Washington. The document contains the parties' information, the vehicle's specifics, and the sale price. The forms include a property description, purchase price, date of sale, and other terms of the transaction.