If you have both a MacOS computer AND an iPad, you can use the free / included software program "QuickTime Player" to share your iPad screen LIVE during a videoconference with students. The steps and video below show you how.
Preparation Part 1: Trust
Plug your iPad into your MacOS computer with the USB charging cable.
On your iPad, click TRUST this computer when prompted.
In the computer's Finder, click the icon for your iPad and click TRUST.
Preparation Part 2: Authorize
If you are running the latest MacOS Catalina (10.15.3) you will need to authorize SCREEN RECORDING in System Preferences:
Start a videoconference with your preferred platform and SHARE YOUR SCREEN.
From the Apple Menu, select System Preferences, Security & Privacy
Scroll down to SCREEN RECORDING.
Click the lock in the lower left corner and login with a local administrator account.
Click the box next to your videoconferencing application (Google Chrome for Hangouts Meet, GoToMeeting, Zoom, etc.)
Open QuickTime Player software (from your Applications folder)
From the FILE menu choose NEW MOVIE RECORDING.
Click the "down arrow" to the right of the red record button in the center and select your IPAD NAME as your video source.
Open your desired Whiteboard app or other iPad app and use your Apple Pencil / other iPad stylus as desired to draw and annotate as desired in the live videoconference.
TIPS: Be sure to rotate your iPad so it is in LANDSCAPE mode, not PORTRAIT mode. Resize the QuickTime Player window so it fills the screen.