Is there a way I can send a group email using Allmoxy?
There's not a way to just send a one-time email out to everyone - your options are really just triggers OR you can create an announcement that everyone will see as soon as they log in to your instance.
If you want to send out a mass email to all of your customers, we recommend using a 3rd party campaign manager like MailChimp and exporting all of your contacts. Importing is easy! A service like Mailchimp can also notify you if you have bad email addresses for contacts.