Automated email to non-user email address

I believe that you need to contact support and have them flag your account to be able to send emails to someone outside of the app.

Thanks Austin.

You can make an Open Notification to got to anyone, including on users.  Where it says where to send the email to, you can type in the field name(s) in the box like this
[email 1]
[email 2]
[email 3]

The email can be triggered by manually editing a record, or you can make a formula URL button to toggle a checkbox field to trigger the email.  But these cannot be sent out based on a Subscription as Subscriptions only got to Users.

If you have a lot of emails to trigger it is possible to set up a script to trigger all the emails for a particular report by clocking just once to initiate the script.