In the browser on my iPad, the student's submission shows with all the annotation tools.  However, when I try to underline or highlight with either the Apple pencil (or my own finger), the document moves.  No line or highlight is made except a short line that is not where I put down the Apple pencil.   When I change to the typing icon, select font size then touch the workpiece, the workpieces minimizes.  

In other words, none of the annotation tools seem to let me annotate on the document.  

What am I doing wrong?