A welldrafted purchase agreement protects the interests of all parties involved, ensuring a smooth transition from offer to closing. A Texas residential purchase agreement outlines the terms and conditions of an offer to purchase real estate.The sale actually consists of two transactions: 1) transferring the property to the buyer, and 2) paying off the existing mortgage on your home. A real estate purchase agreement is a fundamental component in property transactions. It serves as a legally binding contract between the seller and the buyer.