A Pennsylvania vehicle bill of sale is a legal document formalizing the sale and purchase of a motor vehicle between a buyer and seller. A Pennsylvania Trailer Bill of Sale is a critical document that can help protect your legal rights.The Trailer is to be sold free and clear of any liens, encumbrances, or mortgages. Looking for a Pennsylvania bill of sale? We provide a free printable form with detailed guidelines and a document maker for custom forms. This form is used to obtain a Pennsylvania Certificate of Title for vehicles not currently titled in Pennsylvania, or which were repossessed (1.