Keep uninvited people from joining your meeting by locking it after you start it. If you don't lock your meeting, anyone who has the meeting link can join it. When you lock a meeting, you can see who's waiting to join and let individual people in, or let everyone in at once.
During the meeting, go to More , and then select Lock meeting . You'll see the lock icon at the top of your screen to let you know that the meeting is locked.
To unlock the meeting, go to More , and select Unlock meeting .