A single free-format textual comment can be associated with the solution (menu option Solution | Comment).   Maximum length is 256 characters.

Comments can also be added to the drawing surface :

The new comment box will appear at the cursor location.

The comment box menu can be accessed :

Text can be entered by selecting "Text".   The Text dialog allows entry of a single line of text, up to 256 characters.   HTML line breaks ("<br>") can be inserted so the text will appear as multiple lines.

Comment boxes can be dragged to any location on the drawing surface and resized with the mouse.

Comment boxes can be deleted by selecting the box and pressing the Delete key, or by using the comment box menu Delete option.