Each registered user has the option to display or not display their email in their account settings.

DiscApp Admins do not have access to the list of registered users as the same registration can be used
on all DiscApps. You can search users by the name they use to post on your DiscApp and block them that
way. You can also turn moderation on and preview posts from your maintenance page before approving
them for public view. This DiscApp has moderation turned on and all posts go into a queue for approval.
When you see a problem poster in the moderation queue, you can block that person before his posts are
seen.