The classic whiteboard feature will allow you to share a whiteboard that you and other participants (if allowed) can annotate on.
Note: Classic whiteboard is different from the new Zoom Whiteboard which is a persistent digital canvas. Read the Zoom Whiteboard support guide to learn more about the new Zoom Whiteboard.
If you have simultaneous screen sharing on, multiple participants will be able to share a whiteboard at once. However, to see two whiteboards at once, or your own whiteboard and another participant's, you will need to have dual monitors enabled.
Note: Whiteboard is currently available for iPad only. If you are on an iPhone, you will not see the Whiteboard option.