These text annotations consist in adding a graphical effect on existing text.
To highlight, underline or strikethrough some existing Text:
In the Annotation pane:
Select one of the three types in the drop-down list of Annotation types
Create your highlight, underline or strikethrough by selecting the text into the image view
The Annotation is created as soon as the selection is done
Edition options:
The color of the annotation: quick color selection or advanced color selection
Add a Comment: in some PDF viewers, this comment is shown when the mouse cursor runs over the marked text.
Note: For one same text selection, the type cannot be changed/edited after saving. It has to be removed and recreated.
For more general information on annotation mode, see chapter Using_Annotations.