This tutorial explains how to enable a Newsletter registration form to be pre-filled from a pre-existing Login App user session.
As soon as the Login App is installed and your web pages are prepared for client-side usage of the Login App as described in Login App Setup client-side login form you can proceed to implement a Newsletter registration form.
Create Newsletter App instance
Go to Tools / Apps / Newsletter and create a new instance:
 | Enter an appropriate Title. Select English as the Used language. |
 | Remove the Category field from the Form wizard. |
 | Add least one Default list, create a List if necessary. |