This authorization letter allows a representative to transfer ownership of a vehicle on behalf of the lawful owner. How to fill out the Letter of Authorization for Vehicle Use?1. Enter the owner's name and identification number. 2. Visit a motor vehicle agency to transfer the title, complete the Vehicle Registration Application (Form BA-49) if applicable, and receive the license plates. Edit, sign, and share authority letter online. No need to install software, just go to DocHub, and sign up instantly and for free. A title determines vehicle ownership. When you buy or inherit a vehicle, the title must be transferred into your name to verify the ownership has passed.