Hi @Nico Zhao
Based on your case description, you cannot add required attendees when creating a meeting.
According to our test, we can see the "Add required attendees" or "Add optional attendees" box option when scheduling a meeting in the calendar. Please make sure your Teams client is up to date.
In addition, please try to log in to the Teams web client and create a meeting to see if this problem also occurs. During this period, please invite others to the meeting through the meeting link.
If you still have issues, please report the issue in the Teams client here.
Or you can log in to the M365 admin center and report the problem. Teams will investigate the problem and deploy a solution after receiving the feedback.
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