Microsoft 365 (Calendar, Email and OneDrive)
Where do I get my authentication credentials / tenant ID?
To obtain your Microsoft 365 tenant ID, login to Microsoft 365 by navigating to https://entra.microsoft.com and logging in to your account as the main Administrator.
Once in the account Navigate to Admin -> Azure Active Directory -> Azure Active Directory -> Overview
Your Tenant ID will be shown at the top of your overview page and will be in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:

When you enter your Tenant ID it can be in either of the above formats and the user will be an email address of someone who has a Microsoft 365 account.