You will sign the purchase offer and your agent will present it to the seller's agent along with your mortgage pre-approval letter. Explain why they should pick you.Once you've found the home you wish to purchase, I'll guide you through making an effective offer based on property and market conditions. Theoretically, you could write an offer on a restaurant napkin but nearly all Arizona home purchase offers are written on pre-made contract forms. Want to Stand Out From The Competition? What is the legal address? Conditions: Specify any conditions that must be met before a final agreement is signed. An Arizona residential purchase agreement is a legal document outlining the terms and conditions for a buyer's purchase of residential property from a seller. Mahan suggests making the offer letter more about the house versus the people living in the house or the family that's trying to buy the house.