Newsletters: Import Settings
Newsletters > Configuration > Subscribers > Import Settings
Email Notification After Import
Enable this option to receive an email notification on the administrator email address after the import queue has finished importing.
Create Field Options
Turn this option on to automatically create field options during import if they don’t exist.
For example, you have a checkbox custom field under Newsletters > Custom Fields and you are importing a CSV file with a column that contains comma separated strings/values that you want to import into this custom field. The options that do exist on the checkbox custom field already will be imported but usually the ones that don’t exist on the custom field will be skipped. With this turned on, the field options that are in the CSV file but don’t exist on the custom field will be added to the custom field automatically.