Motor Vehicle, Mobile Home, Off- Highway or Vessel Description. Year. Visit the California DMV's website and download a bill of sale.We will be addressing how to fill out a bill of sale form for the sale of a car so let's get started with this guide to filling out a bill of sale form. Complete the new owner information on the back of the certificate and sign it. Bill(s) of sale, if needed to establish a complete chain of ownership. Need to write a bill of sale? Click here to follow a step-by-step guide and learn the 15 key elements that must be included in 2023.