Your Office 365 tenant ID is a globally unique identifier (GUID) that is different than your tenant name or domain. On rare occasion, you might need this identifier, such as when configuring Windows group policy for OneDrive for Business.
If you do need to find your Office 365 tenant ID, it's pretty easy. Choose one of the following procedures.
Use the Azure AD portal
Office 365 uses Azure AD to manage user accounts.
You can find your tenant ID in the Azure AD portal. You'll need to be an Azure AD administrator.
To find your Office 365 tenant ID in the Azure AD portal
Log in to Microsoft Azure as an administrator.
In the Microsoft Azure portal, click Azure Active Directory.
Under Manage, click Properties. The tenant ID is shown in the Directory ID box.
Use Windows PowerShell
You can use Windows PowerShell to find the tenant ID. You'll need the Microsoft Azure PowerShell module.
Open a Microsoft Azure PowerShell command window and run the following script, entering your Office 365 credentials when prompted.
Your tenant ID is listed in the output.