Comments in Microsoft Word appear to anyone who opens a document, offering a way to leave notes for group editing and collaboration. If you have Word 2013, you can also reply to other users' comments, making it easier to follow back-and-forth comments between editors. Word 2013 also added the ability to hide comments after reading them.
Creating and Hiding Comments
To leave a note in a Word document, select a word or line of text, click "New Comment" on the Review tab and type your comment in the text box. In Word 2013, press "New Comment" with the text cursor already inside a comment to leave a reply. To remove a comment permanently, select it and click "Delete" on the Review tab. If you have Word 2013, you can instead right-click the comment and choose "Mark Comment Done" to hide it. You can hide all comments by clicking "Show Markup" on the Review tab and unchecking "Comments." The nearby "Track Changes" button instructs Word to highlight every change made to the body of a document -- useful for following edits from different users -- but has no effect on comments.
Working With Different Versions
In addition to the new commenting features in Word 2013, the 2013 edition also changed how comments appear. In Word 2010 and older versions, comments would always appear unless you disabled them. In Word 2013, text with an attached comment displays a balloon on the page. Click the balloon to switch from Simple Markup mode into All Markup mode and read the comment. When sending documents to people with older versions of Word, new features from 2013 won't carry over, so plan accordingly: People using older versions can't see if you mark a comment done, and replies to comments appear unthreaded, making them look like top-level comments.