The California bill of sale form helps individuals document data on a transaction involving the sale, trade, or gift of personal property. A California motor vehicle bill of sale is part of the vehicle registration process.Use a free template to write your own bill of sale. California Motor Vehicle Bill of Sale ✓ easily fill out and sign forms ✓ download blank or editable online. With DocHub, making changes to your paperwork takes only some simple clicks. The California bill of sale form, REG 135, allows a buyer to purchase a motorized vehicle or vessel in the State. Next, provide the seller's and buyer's information, including names and addresses, along with signature confirmations.