sales contract; bill of sale
A formal written agreement documenting the sale and transfer of ownership of goods or property.
We prepare a sales contract for the real estate.
Please sign the bill of sale.
売買契約書 is a broader purchase and sale agreement, while 売渡契約書 specifically focuses on the seller's obligation to transfer ownership.
Compound of 売渡 (sale, transfer) + 契約書 (written contract).