The motor vehicle seller must insert the sales price, nonresident state and Arizona county tax rates and complete all mathematical calculations. An Arizona motor vehicle bill of sale is part of the vehicle registration process.You can use our free template to create your document. An Arizona motor vehicle bill of sale (ADOT Form 48-2004) is a legal document that transfers ownership of a motor vehicle from a seller to the buyer. A vehicle private sales receipt serves as formal documentation provided to a buyer as evidence of payment for purchasing a car from a private seller. If you have a written contract, the seller must live up to the promises stated in the contract. A vehicle sales agreement is a lawful arrangement summarizing the terms and conditions of a vehicle sale between a customer and a seller.