How can I add my email address to iMessage and FaceTime?

Hello! I'm trying to add my email address so that my phone and email can receive both facetime and messages. But when I go to settings to add my email, the facetime button is grayed out - and the add email is also grayed out so I don't know how to add my email. Only my phone number is receiving messages/facetime.

[Re-Titled by Moderator]