Turning on Track Changes gives you and others sharing your document a way to make changes that are easy to spot. The changes are like suggestions that you can review, and then remove them or make them permanent. Turn Track Changes on and off by going to Review > Track Changes. When it's turned on, deletions are marked with a strikethrough (All Markup above), and additions are marked with an underline. Different authors' changes are indicated with different colors. When it's turned off, Word stops marking changes, but the colored underlines and strikethrough are still in the document.