Bill of sale, invoice or other sales document – minimum requirements. Clearly print or type all information, except signatures.Baldwin County has its own official bill of sale form that can be found here. The form must have the vehicle details, purchase price, and the seller's signature. The seller must authorize the form before a notary public. An Alabama bill of sale records a transaction between a seller and buyer of goods. It includes the buyer and seller's name, property details, purchase or trade.