Gregg-9111, Firstly, please accept my apologies for the late response on this.
The App Service authentication/authorization module is enabled and configured through the Azure portal and app settings. So, you have to deploy the WebApp and then enable authentication, this will create an app registration for App Service Authentication.
Kindly refer these docs for more info:
Add authentication to your web app running on Azure App Service
Authentication and authorization in Azure App Service and Azure Functions
If you have any further questions, please let us know we will be more than happy to assist you further.