Signature of Seller. This is typically one of the first items you'll put on the bill of sale.A Recreational Vehicle (RV) Bill of Sale is required anytime an RV is sold or transferred between a seller and a buyer. A bill of sale allows the seller and the buyer to complete the transfer of ownership in a legal and safe way. How do I fill this out? A completed Application for Texas Title and or Registration (Form 130-U); Applicable fees.