Changing Editing Activation Email

Hook the ‘retrieve_password_message’ filter for the message body and ‘retrieve_password_title’ for the subject. These filters are applied in wp-login.php around line 348.

This is the same email that is used when someone resets their password when they’ve lost theirs. There isn’t a separate registration process. The new user is fully activated from the start, but they do not know their password. This is how they get it. If you need to handle password resets differently than registrations, check the registration date of the user. The reset key is good for 24 hours. If they’ve registered less than 24 hours ago, it’s very likely a new registration.