To control comment visibility,

1. Select the document text where you want to insert the comment. Click the Comment icon in the pinnable tool pallet.
   Alternatively, go to the Review mode and click Add Comment or click More  > Insert tab > References and comments > Comment icon.
2. Type your comment in the box and click Add.
3. Click the Visibility icon to change the comment visibility settings. You can make the comment visible to all collaborators or only you or add custom settings to suit your needs.
   
   • All collaborators: The comment will be made visible to all the collaborators.
   • Only me: Only the comment owner can view the comment.
   • Custom: Custom settings will let you choose specific users or groups to view your comment. For example, if you want the people within the organization or people from the client-side or reviewers to view the comments, you can use this option.

You can change the visibility while you are adding the comment or after adding the comment. The document owner and reviewers will have full control over the comments they have added to the document. They can choose specific users to view the reply to the comments. By default, the comments are visible to all the collaborators of the document. You can change the visibility of your comments anytime or change it while adding your comment.