If the New York State transferable registration is lost, the current owner can apply for a duplicate registration document at a DMV office. The proof of sale for a vehicle from a dealer is the Retail Certificate of Sale (MV-50) ("Dealer's Bill of Sale").Simply go to where you bought the car. That is unless you bought it off an individual then your title becomes your proof of sales or what your bank provides. A bill of sale is a legal document that serves as proof of purchase and, in some cases, records a transfer of ownership — in this case, for a vehicle. You can contact the seller to ask for a replacement title. The seller can apply for a replacement title at the County Tag Office. Bought a Vehicle Without A Title? Today we're going to be going over filling out a New Jersey title as if you were buying the car from a private seller. Visit a motor vehicle agency to transfer the title, complete the Vehicle Registration Application (Form BA-49) if applicable, and receive the license plates.