Set default value of the 'From' field in workflow email alerts

Default value in workflow email alert 'From' field

• Current User's email address - This is the user that caused the workflow rule to fire.
• Default Workflow User's email address - The Default Workflow User is specified here: To define a default workflow User, go to Setup and enter Process Automation Settings in the 'Quick Find' box.
• An Organization-Wide Address - Your organization-wide email address. To define an organization-wide email address, go to Setup and enter Organization-Wide Addresses in the 'Quick Find' box.

• From Email Address-  On the workflow rule, click on a new email or edit next to an email action. From here scroll to the bottom of the page and select "From Email Address"

Notes: 

• In order to use a company email address, it must first be created as an Organization-Wide Address and verified. The steps to set this up can be found in Salesforce Help, under Set Up Organization-Wide Email Addresses.
• An Organization-Wide Address will not be available until the confirmation email has been verified.
• The user specified for the Default Workflow User should verify their email address through Salesforce prior to designating them to this field.