When integrating with Azure Services regardless of what the service is, you are commonly required to provide a Tenant ID which is sometimes refered to as a Directory ID. This is a GUID that is used commonly for API access. Some tools skip the Tenant ID and request a Tennant Name? What is that?
Open Azure Active Directory
Log into the Azure Portal and navigate to the All Services Search and enter “Active Directory”
Custom Domain Names
Once you are in the Active Directory Blade search for “Custom Domain Names”
The Tenant Name is the domain name.