The offer to purchase lists things like the price you are willing to pay and other conditions of the sale. The offer to purchase is presented to the seller by your real estate agent. You can withdraw your offer only if the seller has not already signed it. If the seller accepts your conditions and signs the offer to purchase, the form becomes a sales contract. You cannot change any of the conditions of the sales contract without additional negotiations and possibly loss of money.
Standard forms make the process of preparing an offer easy and almost risk free.
The standard form provides much of the legal language your offer should contain and identifies many of the items you will want to include. However, you must make many important decisions. If you have questions, consult a real estate attorney. It is easier and safer to consult an attorney while you are completing the offer to purchase than to try to correct mistakes after the sales contract has been drawn up and accepted. The value of every house is assessed by local governments for tax purposes.