Zoom Annotate on iPad - Where has the pen icon on iPads moved to?

[Cavy]

I am an online tutor teaching young Chinese children. In the past couple of weeks, some of my students on iPads have reported that the "pen"  icon is no longer where it used to be and they cannot find it. They need to be able to annotate when I share my screen and they can't now. I am guessing it is an update on their end. As mentioned, they are young Chinese kids with very limited English, and their parents have limited English, too. I have not got info on their devices other than they are iPads. Any hints as to where they will find it? Your speedy assistance would be greatly appreciated - not very productive classes for students without them being able to annotate. Thank you! I have a Dell Core i7, 10th gen, and Windows 10. Zoom version 5.16.2.