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.You'll need to sign the car purchase agreement (or dealer bill of sale), the title, an odometer statement, and sometimes a damage disclosure statement. Regardless of how you acquire a vehicle you should: check the vehicle history, transfer ownership and register your new vehicle. Anyone whose name is on the title will need to be present. The white copy is always submitted to PennDOT. 2.