Comments

This section describes how to add comments in any UML diagram on any element.
You can add Comment inside the diagram using the toolbar and then drag and drop from the toolbar to the UML editor.
 

Comments can also be added on any element of any UML diagram.Select the element and open the popup menu > New > Comment

Insert the comment in the text field and click on the Ok button. You can have a two line comment by clicking not the enter button.

Get you comment in your class  diagram