Subscribers to your Newsletter receive messages that you find on Newsletter> Subscribers management.
Each internet user is free to subscribe and to unsubscribe according to their wishes through your website. Internet users who register through your site become your subscribers to whom you can send your Newsletters.
You can create a text file (.txt) to import a list of e-mails. To do this, save your text file with an email address per line and then import your file to establish or expand your customer base.