Participants can join or monitor multiple meetings or webinars simultaneously using the Zoom desktop app. For more details, please visit our support page.
Q.Troubleshooting black screen during screen sharing
If your screen goes black during screen sharing in a meeting, please try troubleshooting using the following support page as a reference. Additionally, changing the setting under “Settings - Share Screen - Advanced - Screen capture mode” from ‘Auto’ to “Capture with window filtering” may also resolve the issue.
You can change the participants (host only / all participants) who can share screen from the "Settings" of {+}Zoom web portal. "Settings - Meeting tab - In Meeting (Basic) - Screen sharing"