As a seller, you can use either to protect your interests, though they are not the same. The primary difference is that the Sale of Goods Contract is typically more detailed. By virtue of its contractual nature, both parties get to define every term and description in detail, including the shipment of good and payment terms, the warranty. and more. In contrast, a bill of sale serves as evidence that the ownership of goods has transferred from the seller to the buyer. The two documents are not one or the other, as a bill of sale can be used together with a Sale of Goods Contract.