To read data from the user claim object in the e-commerce web app, what should you do first?

The correct approach is to modify the e-commerce web app to read values from the HTTP request headers. When a user authenticates with Azure Active Directory (AAD), AAD issues a token containing user claims. This token is then sent with subsequent requests as an HTTP header (typically Authorization: Bearer <token). The web app can parse this header to extract the user claim object and access the user's information. Calling Microsoft Graph is unnecessary for simply reading existing claims, as the claims are already present in the token. Assigning the Contributor RBAC role is for authorizing the web app to manage Azure resources, not for reading user claims. Enabling CORS is for cross-origin resource sharing issues, which is unrelated to reading user claims from an authenticated request.