How do I fill this out? To fill out this Maryland Trailer Bill of Sale form, gather the necessary information from both the seller and buyer.The bill of sale should include the sale price, the trailer identification information (make, model, VIN), and the signatures of the buyer and seller. A Maryland trailer bill of sale aims to facilitate accord between buyers and sellers when exchanging personal property. You will need to fill out the form and provide all necessary documentation. The MVA provides a Bill of Sale form. Get DMV bill of sale in Maryland online for free. Create BOS document and download for any car, auto, motorcycle bill of sale as per Maryland state laws. To begin the process of filling out the Maryland Trailer Bill of Sale form, click the button below. Launch Trailer Bill of Sale Editor.