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. IN WITNESS WHEREOF, the buyer and seller agree to the terms of this Bill of Sale on the ____ day of.How do I fill this out? Forms on this website are PDFs with fillable fields. Forms should be downloaded to your computer before filling in the fields. You should attach a copy of the bill of sale as proof of the purchase price. An Illinois motor vehicle bill of sale documents the purchase and sale of a motor vehicle between a private seller and buyer in the State of Illinois. By properly completing your vehicle title and registration applications, our office can process your request more quickly and efficiently. This guide provides detailed instructions for completing paper forms. 312 w meadowview rd.