In this guide, we're taking an in-depth look at a Texas Purchase Contract, what each section means, and what you should look out for. The effective date should always be filled in on page 8 of the contract and the responsibility for completion falls to the Realtors involved in the transaction.First and foremost, the contract must identify the parties involved: the buyer and the seller. PARTIES: The parties to this contract are. (Seller) and. (Buyer).