In order to test Azure AD B2C policies during the development phase, administrators can generate test links to invoke and run a policy through the Azure Portal. In order to configure the test link, you need to select an application and reply URL.
Over the next few weeks, we will be making a modification to the "Select application" drop down so that you will only be able to select applications created through the Azure AD B2C applications menu.
Azure AD applications were originally shown in the drop down for legacy reasons, and we are now hiding them to simplify the experience. The change will not have any impact to your existing applications that are running in production. It will only affect the test links generated through the portal.