The below article explains how to use the Black Pearl Mail Follow feature.
By placing [follow] at the beginning of your email subject (including the square brackets), you will receive an email notification when your email has been opened by the recipient. Note that the [follow] is stripped from the email when it is sent, so the recipients will not recieve it. This is a powerful tool for email transparency, and brings about confidence in an otherwise blind world of email delivery.
If you have any questions please don't hesitate to contact support on email@example.com or log into Black Pearl Mail and click on Live Support
Also, note that you are not guaranteed to be notified if a user opens an email. There are certain situations (such as when a user does not display images in your email). However, if you do receive you a follow notification you can be sure they have opened your email.
As always, we're on hand if you get stuck - just email us on firstname.lastname@example.org or log into Black Pearl Mail and click on Live Support