Permissions.md

You need to register following MS Graph permissions in your Azure AD.

Permissions

Permission Name	Permission type	Objective
Calendars.Read	Application	Read schedule information including attendees and online meeting url
Calls.InitiateGroupCall.All	Application	Create group call, Invite user to call
Calls.JoinGroupCall.All	Application	Join existing meeting
User.Read.All	Application	Get user id from email

Reference

• Graph permission all lists and details is described in here
• If you are not familiar with Azure AD permission configuration, you can refer this document.