Explanation
Get an access token.
Note: The Outlook REST APIs require a bearer token in the Authorization header. Typically, apps use OAuth2 flows to retrieve a token. However, add-ins can retrieve a token without implementing OAuth2 by using the new Office.context.mailbox.getCallbackTokenAsync method introduced in the Mailbox requirement set 1.5.
After your add-in has the access token, item ID, and REST API URL, it can either pass that information to a back-end service which calls the REST API, or it can call it directly using AJAX.
Reference:
https://docs.microsoft.com/en-us/office/dev/add-ins/outlook/use-rest-api

Explanation
For the event, group event, group post, message, personal contact, task, task list resource types, you can use the same REST request as getting the resource instance, look for an extension that matches a filter on its id property, and expand the instance with the extension. The response includes most of the resource properties.
Example: GET /users/{Id|userPrincipalName}/events/{Id}/extensions/{extensionId} Reference:
https://docs.microsoft.com/en-us/graph/api/opentypeextension-get

Explanation
Text Description automatically generated

Box 1: $select=..
Example:
GET https://graph.microsoft.com/v1.0/groups/{id}?$select=displayName
Header: Authorization:Bearer {access_token}
Box 2: &$orderBy=Displayname
Order by title.
Reference: https://stackify.dev/185172-how-to-get-users-group-name-from-azure-active-directory-in-angular

Explanation
Scenario: ADatum identifies the following technical requirements for the planned E-invoicing capabilities:
* Ensure that all operations performed by E-invoicing against Office 365 are initiated by a user. Require that the user authorize E-invoicing to access the Office 365 data the first time the application attempts to access Office 365 data on the user's behalf.
Reference: https://docs.microsoft.com/en-us/graph/permissions-reference