How can I disable members of Teams to start call

MichelleHe 

You can consider managing only organizer can start the meeting:

Change participant settings for a Teams meeting - Microsoft Support

Hi MichelleHe
I am looking for the same feature and it looks like that Microsoft didn't release it yet.
I found two feature proposals that we can vote for in order for this to be moved forward with Microsoft.

1: https://feedbackportal.microsoft.com/feedback/idea/3f2963cf-0e59-ec11-a819-6045bd7f58fb

2: and similar subject:
https://feedbackportal.microsoft.com/feedback/idea/03d2cb41-1773-ec11-a81b-6045bd7bf64c
 

MichelleHe Hi Michelle i have the same issue. There's a corporate team and i want that only owner can start meeting. Have you solved this case?

MichelleHe Hello, not sure I understand your question but there are many meeting policies you can configure https://docs.microsoft.com/en-us/microsoftteams/meeting-policies-in-teams

If you talking about the lobby and perhaps only some meetings you can enter the "Meeting options" for the specific meeting and choose 'Only me' from the "Who can bypass the lobby" setting.

Change participant settings for a Teams meeting

https://support.microsoft.com/en-us/office/change-participant-settings-for-a-teams-meeting-53261366-dbd5-45f9-aae9-a70e6354f88e