Both parties are required to sign. The DMV recommends that both parties jointly visit a County Tax Office when the seller is signing over the vehicle's title.The Texas bill of sale form verifies the elemental facts of the sale of personal property in exchange for a predetermined compensatory amount. Learn More About the Importance of Bills of Sale in Texas When Documenting the Sale of Personal Property to Another Individual or Entity. While it is common to present a bill of sale in a digital format, you can also create this type of contractual agreement as a handwritten document on paper. Yes I mean the bill of sale. This video will show you how to fill out your Texas title, notice of vehicle transfer, and application for title. Signatures authenticate the agreement and make the bill of sale legally binding. Without signatures, the document isn't valid. Notarization. A bill of sale is a legally binding document that shows in writing the sale or transfer of personal property from one party to another.