You may want to disable public sign ups to allow only certain people to access your app.
From an email password login point of view, the flow would be disable the sign up API and to manually create users and send them an invite link. When they click on the invite link, they will be asked to set a password before being able to login.
From a third party login perspective, you would want to maintain an allow list of emails and only those users would be able to login to access the app.
In this section, we will see how to achieve both of these flows.