@Amie Winchester you can get email address from Trello username, but there is a little hack these days with the Butler power up which has the ability to send notifications via email to members of a card or board:
It's only on paid accounts, though. Otherwise you can just mention them in a comment and they'll get a notification anyway.
Hello Community! My name is Brittany Joiner and I am a Trello enthusiast and Atlassian Community Leader. I'll be sharing with you a series of videos with my top tips on how to best use Trello...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events