Appraise-It includes an automatic adjustments feature, which will calculate adjustments in your report's sales and listings grids based on the subject and comp or listing data.
In general, for supported comp grid line items, Appraise-It will subtract the comp's description value from the subject's, then multiply the result by an adjustment factor you specify on your adjustments addendum.
Specific adjustment methods are explained in their own articles, linked below. Multiple adjustment methods can be used in each report, allowing for quick calculation of comp adjustment values.