Apply for a title within 15 days of purchase and take the application to an MVD Office or Authorized Third Party provider to complete the process. An Arizona Certificate of Title for a vehicle, when properly assigned and endorsed, is your proof of ownership document.Adding your spouse's name to your vehicle's California Certificate of Title is simple if you've got the right paperwork filled-out. To transfer a vehicle with a power of attorney document, you need to draw up that document first. Generally, the certificate of title is proof of ownership of a vehicle. However, if there is enough evidence to the contrary, ownership may become a question. You have to go to the website for your state's DMV. There's a fee for printing out a duplicate. Generally speaking, both joint owners are required to sign transfer documents. Pennsylvania requires notarized title transfers and on top of that there is no bonded title process, so there are plenty of cars floating around with no titles.