Yes, you need a bill of sale. State the terms and odometer reading on the BOS.In a private sale, have the seller make out a bill of sale in addition to the ownership and sales tax documents. Next Section. Continue. What should you include in your vehicle bill of sale? Payment details: Write down the sale price and how you agreed to be paid. In most cases, the buyer will pay a lump sum. To fill out the bill of sale form you'll need the name and contact details of the buyer and seller.