You can highlight text in any article in your library and/or add an in-line comment to text.
Select the text you want to annotate then choose Highlight or Comment from the small pop-up box that appears above the selected text.
Comments will appear in the right-hand column, next to the article.
You can also write general notes about an article.
To add a general note to an article, simply click the article, and fill in your note in the field below the abstract in the right-hand pane of the application.
OR
When reading an open article, click the “Notes” button in the dark grey bar near the top of the application window.