Schedule a meeting between yourself and the other party. (You can either be the seller or the buyer in this scenario.) You both must be present to accurately fill out the form. You should consider filling out the Addendum with your mortgage broker present.
Fill out the first page of the Addendum. Information that needs to be completed includes: date, mortgage amount, property address, type of mortgage (fixed, variable, adjustable), interest rate, term (length) and a declaration of Written Statement. The Written Statement gives the seller notice of the buyer's intent to purchase the property. If the buyer opts for a Written Statement when completing the Addendum, both parties agree to sign a Cancellation Letter if the financing falls through.
Fill in the information on page two of the Addendum. This information includes: property address, when the rate will be "locked" (held for a predetermined period of time), an indication of who will pay reinspection fees, a declaration of lender processing fees and the sale price of the property in question.
Make two photocopies of the Financing Addendum. The original copy goes to the lender, one copy to the buyer and one copy to the seller. Retain this document in your records pertaining to your mortgage and house.