Protect your interests when buying or selling a vehicle in New York. Save time and stress with our vehicle bill of sale template.The final hurdle you face is signing the vehicle purchase agreement; a confusing and convoluted document that we explain in detail here. How to submit this form: Submit this form along with required documents and applicable tax to the county tag office in the county where the primary purchaser. I sold my car, what do I do? If you are in doubt concerning the transferring, buying, selling or mortgaging of a motor vehicle, always call your Clerk of Courts for complete information.