In order to send emails to your users using Adastacks, you must first give Adastacks permission to use your email address on your behalf. This is where verified emails come in. Any emails that you verify in Adastacks can be used as "From" addresses in email-based stacks. But beware, you can only verify emails on domains that are not third-party. Emails from Gmail, Yahoo, iCloud, Hotmail, etc. cannot be verified with Adastacks.