The config contains system wide settings. In the following we explain some important settings which you most likely need to configure.
If a new user registers through the consumer app he receives an activation mail. Through this setting you can configure the text and adjust the activtaion url
If provided the consumer registration can show an google recaptcha which prevents automatic registration. You also have to provide the recaptcha public key to the consumer app
Those are the scopes which are assigned by default if a new user registers
If provided a user can login through those remote providers. You also have to provide the app key to the consumer app