Explanation:
Graphical user interface, text, application Description automatically generated

* Create an app registration:
Your app must be registered with the Microsoft identity platform and be authorized by either a user or an administrator for access to the Microsoft Graph resources it needs.
* Grant admin consent:
Higher-privileged permissions require administrator consent.
* Add app permissions:
After the consents to permissions for your app, your app can acquire access tokens that represent the app's permission to access a resource in some capacity. Encoded inside the access token is every permission that your app has been granted for that resource.
Reference:
https://docs.microsoft.com/en-us/graph/auth/auth-concepts