Other applications that use a similar annotation toolbar have additional abilities for adding items onto the PDF that is being annotated.
- add an image from the photo library or camera directly
- copy/save annotations for pasting later in the current document or future documents
- stamp annotations
- add an audio file
- lasso a group of annotations for moving, deletion, color change, etc.
Currently, there is no method in Canvas for these.
Original question thread: PDF Annotation Tools