Mobile Home, Off-Highway Vehicle or Vessel. How do I fill this out?To fill out the Florida Trailer Bill of Sale, gather all necessary information about the seller, buyer, and trailer. The seller and the buyer must fill out sections 1, 2 (if applicable), and section 3 to finalize the deal. POWER OF ATTORNEY FOR A MOTOR VEHICLE, MOBILE HOME, VESSEL or VESSEL with TRAILER. A Florida bill of sale is used for the sale of vehicles, watercraft, firearms, furniture, and other valuables as proof of purchase. Date of Sale: , 20_______. Use the downloadable forms below to print and fill out prior to your appointment for faster service. 4. Complete the Sale. Seller handing car key to new owner.