Email alerts are emails generated by a workflow rule or approval process and sent to designated recipients whenever specific business actions trigger the workflow rule or approval process.
Often the recipients are your users, such as sending an email to the opportunity owner when their opportunity becomes approved, or to sales reps when leads reach a certain qualification status in their territory.
Sometimes, you may want to send an email to a non-user, perhaps to a mail distribution list. This can be achieved two ways, Additional Emails and Email Fields.
1. Additional Emails
Email Alerts have an Additional Emails section that let you enter up to 5 email addresses. These email addresses do not have to belong to users in your Salesforce org. These recipients are in addition to the users chosen in the required Recipients section. I have personally used this feature to copy a customer service mailing list when certain opportunities are approved; the opportunity owner was the primary Recipient.
2. Email Fields
Another option is to choose an Email Field as the Recipient. Any email field on the object associated with the email alert is eligible. Email fields are neat because they can be chosen as the sole recipient of an email alert (if desired) and the field’s value can be set either with default value on the field definition or via field updates. This provides a lot flexibility in who receives email alerts that aren’t actual Salesforce users. I have personally used this feature to send a specific email alert to a distribution list when no actual Salesforce user would be a Recipient.