You can upload a .csv file that includes email addresses in order to add them to your auto-approve list.
First click your publisher name at the top right of your Dashboard to go to Your Account Settings page. On the bottom of this left-hand menu, you'll see an Auto-Approved Members section. Click "Add Auto-Approved Members" to be taken to this page:
Here, you can type in the email addresses of the members you'd like to auto-approve, or upload a CSV with these email addresses. If an email address on that list is associated with a member that has already accessed one of your titles, the member will be added to your auto-approval list. (Note: This initial checking process takes some time, approximately 45 minutes.) You will see this screen:
Members on that Pending list will be added to your Auto-Approved List after they have requested one of your books, or after they click on a widget link that you provide them.
The easiest way to ensure that those "Pending" auto-approvals make it onto your list is to send a widget for a particular title and say something like: “You’re pre-approved for this title, and after you click on this widget link, you will be auto-approved for ALL our titles in future.”