Real estate appraisers must deliver appraisals that meet the minimum requirements of the Fannie Mae Selling Guide for most conventional assignments, and may be required to meet certain additional client-specific requirements that are communicated in each engagement letter. For many Fannie Mae appraisals, appraisers are required to prepare reports according to Uniform Appraisal Dataset (UAD) standards. To view the requirements of Fannie Mae, click on the information linked here.