I have an app hosted in https://mydomain.com/ and I have created a custom domain for auth0 as https://login.mydomain.com/. I am using auth0 lock and I need clarity on the field that need to provide to make my custom domain to work.
That screenshot seems to come from (Configure Features to Use Custom Domains) and as mentioned at that page if you’re using Universal Login with Lock that’s exactly what should be set in the universal login page template. In other words, the config object obtained per the templates will have the correct values.
On the other hand if you’re using Lock embedded in your application you should follow (Configure Features to Use Custom Domains) which does explain the actual values that you will need to use.