The comments tool in PowerPoint is a feature that allows you to add suggestions or feedback to your presentation.

You can use the comments tool to collaborate with others, review your work, or keep track of changes.

To access the comments tool, go to the review tab and click on the new comment button, or click the speech bubble icon on the far right of the ribbon.

You can also view, edit, or delete existing comments by clicking on the previous or next buttons, or by selecting them from the comments pane.

It's also good practice to first click on the text box or shape that the comment applies to as when someone goes over the comment in the comments pane, the specific component will be highlighted that needs updating based on the comment.