Original signatures from buyer or authorized agent. A completed and signed application for Texas title, 130-U.To complete a title transfer, gather the required documents, such as the original title and bill of sale. The process may be easiest if the buyer and the seller go to the DMV together to fill out the necessary forms. Compare Auto Loans in Minutes. Next, provide the names and addresses of both the seller and buyer. We will be addressing how to fill out a bill of sale form for the sale of a car so let's get started with this guide to filling out a bill of sale form. The buyer's full name.