Communication with Azure AD is organized through Microsoft Graph API which provides endpoints for users/calendars/events management.
Emply Peopleuses its own Enterprise Application that is registered in Emply People’s tenant of Azure AD to make it possible to access Microsoft Graph. It’s called Emply People and can be found in Home > [something] > App registrations section of Azure Portal.
This application has permissions to read and write user data and also read/write calendars and events info of a specific AD user. Permissions can be found on API Permissions page under the Emply People App registration.
Emply People app permissions
Note
Permissions should be granted by Global Administrator of the tenant that will use the Emply People app.