Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
Only a user can change their e-mail address. The parent needs to log in then go to My Dashboard → Administration → My Account → E-Mail. They can change their e-mail address there.
This same page has the Messaging Opt-Out switch. It should be moved to the left so that it turns gray.