Microsoft Teams meetings can be locked to limit participants. When a meeting is locked, invitees will still be able to access the meeting chat, recording and other meeting info, but no one else will be able to join.
To Lock a Meeting
1. Start the meeting
2. Click on People at the top of the window
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3. Click on the three dots next to Participants
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4. Select Lock the meeting
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5. In the window that opens, click on Lock
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The meeting is now locked and no one else will be able to join.