PDF Annotations

To annotate PDF documents, you will tap on the "annotate" icon in the top right corner. A tool bar will show on the left side

To type, select the second icon on the tool bar, the text box will appear and you can add the text.

There are many options for annotating like a pen tool, highlighter, adding shapes and images. 

All of the tools with multiple options can be opened up by holding down on the icon.