You can find a sample form here. What's on a Mortgage Interest Statement.Do you need to file Form 1098? This guide breaks down why, how, and when the Mortgage Interest Statement needs to be filed. Obtain forms from either the County Assessor or the Clerk of the Board in the county where the property is located). Master Form 1098, the Mortgage Interest Statement, to maximize your tax deductions with easy steps and FAQs.