Change Default 'From' Email Address When You Send a Single Email or Mass Email

Workaround:

You can change the email name on your My Email Settings before sending the mass email.

Note: If you send through Office 365, you can't change the Email name in Salesforce as directed in the instructions below.  For more information see Considerations for Send Email through Gmail or Office 365.

Steps:

• Salesforce Classic: Click your name | My Settings | Email | My Email Settings
• Lightning Experience: Click your avatar | Settings | Email | My Email Settings

Then on the Email Settings page, change the following fields:

1.  How would you like your name to appear on your outgoing email? 

2. What email address would you like to use as your return address? 

3. Click Save.

Notes:

• The personal email associated with your Salesforce account won’t change.
• When a user is assigned to an Einstein Activity Capture permission set the email name, email address, and automatic BCC fields are removed from the My Email Settings page.
• There are other system settings that control the 'From' as well as the 'Reply' addresses. For example, Send Case Notifications from System Address in Support Settings and Deliverability option in Setup.

Vote and comment on the following Idea on the Salesforce IdeaExchange:  Changing "FROM" address in mass email blasts to send on behalf of other users.