Anyone can share their screen, application window, or file within the meeting, without being promoted. If you previously restricted sharing in your meeting room to hosts and presenters, you'll have to promote the guest to a presenter role before they can share their screen.
Note: Only guests attending via browser or desktop apps can screen share. Screen share is not supported on mobile.
When someone begins sharing, the shared display defaults to Scale to fit. You can change the size of the display using the zoom controls.
To stop someone's content sharing:
Either click X (close) at the right side of the zoom controls or click the share button in the meeting controls and start sharing your own screen, window, or file.
Note: If your room is restricted and the Presenter role is required to share content, demoting the presenter back to the guest role also ends sharing.