A Texas residential purchase agreement outlines the terms and conditions of an offer to purchase real estate. Purchase and sale agreements are important documents that outline the details of a real estate transaction between buyer and seller.Sale and supply agreements vary in length and complexity depending on a variety of factors, such as: ∎ The relationship between the parties. The agreement includes the conditions of a property sale from the seller to the buyer. Purchaser desires to purchase the Property and Sellers desire to sell the Property, all upon the terms and conditions set forth in this Agreement. Addendum for Sale of Other Property by. Buyer. The agreement includes the conditions of a property sale from the seller to the buyer. How do I write a Sales Agreement? For a sample time of the essence provision, see Standard Clause,. General Contract Clauses: Time of the.