In the last few weeks I uploaded material to help instructors transition their classes to Zoom. The first video is a very basic tutorial on how to use an iPad to annotate in Zoom.
The second video covers settings to fight “Zoom-bombing”.
There are some resources that are also useful. In particular, following an internal tutorial I gave on the different ways you can make annotations in zoom, the IT department published a clear description on how you can do it via a drawing pad, a camera, or a tablet. See the information here.