1) Add comments to the whole doc, from the comments panel.

2) Add inline comments attached to specific parts of the doc, by selecting pieces of text, images, sketches, videos, or tables.
Adding comments
Commenting on the whole doc (a.k.a. global comments)
Just click on the speech balloon icon in the top right of a doc to get started. This will open the comments panel on the right side of the document. Then, click "Add a comment..." at the top and start typing.

Click the speech balloon to reveal the comments panel.

Click the box and start typing to add a comment.

Commenting on highlighted text (a.k.a. inline comments)
Highlight the text you wish to comment on and click the  icon in the toolbar.
Alternatively, you can press Command-Option-M to add a comment—try it!

Add a caption...
Tips for writing comments
You can create a line break by hitting Shift-Return .
You can add doc links and mention people in your comment typing @ .
Visualizing existing comments
There are two different ways to notice when there are comments on a doc:

.1Comments panel with all comments
The comment icon  on the top bar turns yellow when there’s an unread comment (this applies to all comments, global and inline ones.)

New unread comment.

In the comments panel, newest replies on inline comments will appear first, followed by global comments.
You can filter comments by open or resolved. Comments on deleted text keep their previous status (open or resolved) and we show the excerpt of the deleted text.

.2Individual comments
Individual comment icons will appear next to each part of the doc when there are inline comments. Clicking on them will display each thread, and you can navigate to the previous or following threads by using the arrows. They'll turn yellow when there's a new comment that you haven't read yet.
Resolving comments
When and how to resolve
You can resolve comments once the points have been addressed, to tidy your doc. Just click on the "Resolve" button in the top right of a thread.

Add a caption...
Viewing resolved threads
Open the comments panel, and on the top left area click the "Open comments" filter. Then, select "Resolved comments" to switch to the resolved comments list.

Add a caption...
Deleting comments
Use the three-dot menu in the top right of a comment to delete it. Deleting the first comment of a thread will delete the whole thread.