Microsoft Graph is the gateway to data and intelligence in Microsoft 365. It provides a unified programmability model that you can use to access the tremendous amount of data in Microsoft 365, Windows 10, and Enterprise Mobility + Security.
Representational State Transfer (REST) APIs are service endpoints that support sets of HTTP operations (methods), which provide create, retrieve, update, or delete access to the service’s resources.
An access token contains claims that you can use in Azure Active Directory B2C (Azure AD B2C) to identify the granted permissions to your APIs. When calling a resource server, an access token must be present in the HTTP request. An access token is denoted as access_token in the responses from Azure AD B2C.