Double opt-in ensures that your learner only receives marketing and promotional emails from you if they subscribe to do so via email. It signals to your learners that you care about their privacy. Furthermore, you can expect higher open rates and thus get more accurate engagement metrics.

To learn more about how to enable double opt-in, please read this article: https://help.graphy.com/en/articles/how-to-enable-double-opt-in-for-your-marketing-emails