Address the Seller and Introduce Yourself. Do you know how to write an offer letter for a house?We're here to teach you the ins and outs to improve your chance of closing a deal. We offer a customizable sample offer letter to purchase property in PDF. Focus on three things: State your intentions, show that you have the financial means to make the purchase and make a personal appeal to the seller. Like any other letter, make sure it has an introduction, a body, and a closing paragraph. Craft a winning house offer letter with our customizable template and tips.