Comments & Changes sidebar
A sidebar (or pane) on the left side of the Pages window that shows comments and tracked changes in a document. You can show or hide the sidebar and filter its contents in various ways.
To open the Comments & Changes pane, click in the toolbar, then choose Show Comments & Changes Pane (or Show Comments Pane if changes aren’t being tracked).
If Change Tracking is on, you can also click on the left side of the review toolbar to show or hide the sidebar.