Note: Any annotations made using the BoardPro Notes iOS app will appear in the Board Pack on the web version and vice versa.
In BoardPro Notes begin by selecting a meeting and tap on it to open up the Board Pack.
Go to the document you wish to open and select the annotation (pencil icon) on the top navigation bar.

On the annotation bar that opens you have the options to
Underline/strike through text
Add text or a signature
Add a sticky note
Use a pencil feature (click on the colour to change colour, font size etc.)
Highlighter (click on the colour to change colour, opacity etc.)
Draw
Eraser
Add Shapes
Add Photos
Click on the "x" to close the annotation feature.
Related Articles:
The Board Pack in BoardPro Notes iOS App
Delete an Annotation in BoardPro Notes iOS App
Find Previous Versions in BoardPro Notes iOS App
iOS App Voice Annotations
Navigating the Menu in BoardPro Notes iOS App