You need to file a report of sale when you sell, donate, or give up ownership of a vehicle. Learn how to report a vehicle sale.Use this form to gather necessary information when you sell your vehicle or vessel. What forms must I fill out? 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 form ensures that the sale and purchase of motor vehicles are legal. How to fill out the Guide to Reporting Car Sale or Purchase in WA? 1. Gather the seller's and buyer's information. 2. 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.