Azure Active Directory (Azure AD) is Microsoft’s enterprise cloud-based identity and access management (IAM) solution
Azure AD is the backbone of Microsoft’s cloud IAM:
Microsoft 365
Azure portal
Other SaaS applications
Azure AD it can sync with on-premise Active Directory and provide authentication to other cloud-based systems via OAuth
Usage
Enterprise Single Sign On (SSO)
OpenID connect integration to applications
OAuth 2.0 delegated access to resources
Identity and Access management (IAM) for organizations
Who uses Azure AD?
IT admins: As an IT admin, you can use Azure AD to control access to your apps and your app resources, based on your business requirements
App developers: As an app developer, you can use Azure AD as a standards-based approach for adding single sign-on (SSO) to your app, allowing it to work with a user’s pre-existing credentials
SaaS (Microsoft 365, Dynamics 365 etc.): As a subscriber, you’re already using Azure AD