When selling a vehicle, the seller must sign and handprint their name on the proof of ownership document. This form is used to obtain a Pennsylvania Certificate of Title for vehicles not currently titled in Pennsylvania, or which were repossessed (1.Please fill out ALL fields on the Bidder Registration form. 1. Enter the Buyer and Seller's details. You can renew your registration, learn more about registration stickers, and discover helpful resources about buying and selling your vehicle.