From the Menu > Presentations.
To turn "on" annotations click the green annotation icon.
The annotation tools appear.
To Unlock Annotations For All Attendees
Mobile Presenter goes to Settings > Unlock Annotations.
To Save The Annotated File As Document Asset Into The Asset Library
Turn Off Annotations
Click the "X".
Note: When annotations are "on", Documents are disabled. To enable access to Documents turn annotations "off". And, to navigate between slides in the presentation, annotations must be turned off.
Saving Files To The Asset Library
These files will be saved to the Session Assets and the Asset Library as a document asset type.