Hi @Ancy ,
Thanks for reaching out to Microsoft.
You can use Change notifications in Microsoft Graph to subscribe to call started/ended and call roster updates for Microsoft Teams online meetings.
Please check the document https://learn.microsoft.com/en-us/graph/changenotifications-for-onlinemeeting
There is no need for any additional license to create subscriptions.
Please check the below document to create subscription. https://learn.microsoft.com/en-us/graph/api/subscription-post-subscriptions?view=graph-rest-1.0&tabs=http
Hope this helps.
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