Azure App Service provides a highly scalable, self-patching web hosting service in Azure. App Service also provides a managed identity for your app, which is a turnkey solution for securing access to Azure SQL and other Azure services. Managed identities in App Service make your app more secure by eliminating secrets, such as credentials in connection strings.
Reference:
https://learn.microsoft.com/en-us/azure/app-service/tutorial-connect-msi-sql-database