Mobile Home, Off-Highway Vehicle or Vessel. Motor vehicles, vessels, mobile homes and trailers must be registered at the point of purchase and a certificate of title issued as proof of ownership.Registering a trailer in Florida requires a Florida trailer bill of sale form. A completed form to title and register a trailer is required. Learn about Florida Bill of Sale requirements. Get forms and templates to document the sale of items such as cars, boats, horses, firearms, and more. Can someone post a sample Bill of Sale for a used boat? If not, maybe some highlights on items that need to be mentioned or included.