If you sell goods to a federal authority, special contractual rules come into play, which impose what must be included in a sales contract. These rules may vary depending on the agency and the nature of the goods concerned. A purchase-sale contract ensures that ownership of a business remains in the hands of the other owners or the business itself if a member withdraws. Learn how to use a buy-sell agreement for your business. Find out what a real estate sales contract does and what it should include. A seller may choose to deliver the goods and later invoice the buyer for payment. Create a custom invoice. While a sales contract and a sales contract have similar objectives, a sales contract offers a more detailed payment plan and offers guarantees for the item. When buying goods, do you use an order or sales contract for your business? To determine this, you need to understand the differences between these two purchase business documents.. .