Go to Manage - Members - Invite Users. You will get a list of everyone without an account. If they do not have an e-mail it allows you to add it right from that screen. I did just notice this is not perfect as I see two users without e-mails in their Profile but the Invite button is available, @Keener-Trooptrack perhaps a bug to look at?
Perhaps the more reliable way would be to use the Manage - Members - User Accounts that shows who does not have an e-mail or account. You can select Actions - Edit and go to their Profile to add an e-mail, then go back and select Actions - Reset Password.