If you are using the 'Workflow Management' feature in SugarCRM you probably already created some basic workflows and ran into the following question: How do include a custom email address in the 'Alert recipients' list?

Here how you get the job done, in my case i am using Opportunities module as an example.

1. Go to Admin > User Management.

Hover with the mouse over the top menu bar in the 'Users' section and click Create Group User (/index.php?module=Users&action=EditView&usertype=group&return_module=Users&return_action=DetailView). Fill the mandatory fields: User Name, Name, Status = Active, Email address

What is a Group User?

According the the Users -> User management section in the SugarCRM Pro Documentation "a Group User is a bucket that is used for inbound emails, and does not count toward the number of Sugar licenses that you purchase for your organization. For example, creating a group mail account for Support creates a group user named Support to handle customer support issues."

In my case i've created a Sales.Test user which in a real world case scenario would represent a general email address like sales@your-company.com, so everytime i change something in an Opportunity the whole sales department would know about it.

2. Next go to Admin -> Workflow Management -> Create Workflow Definition

I've created a workflow called  'Reassign Opportunity' which states that when an opportunity is reassigned to another user, he will be notified but i want also to notify the Sales.Test email address i've just created.

Go to Alerts -> Recipients, click 'Create' button, check 'All users in a specified team', click on the 'Team' link below and select 'Sales.Test', and put it to To: or CC:.

3. Save, go to Opportunity and reassign an Opportunity and you will receive an email on both the currently assigned user and on Sales.Test email address. That's it. 

Conclusion

You don't necessary have to have a registered user to be able to send a workflow email to a certain email address, you can do it with 'Group User' feature described at the top.