Override 'From' address with SingleEmailMessage

How to Override the From Address

To override the From address on a Salesforce Apex SingleEmailMessage, use the setOrgWideEmailAddressId(ID) method. This method accepts the Salesforce ID of an Org-Wide Email Address record and uses that address as the From address when the email is sent.

Steps

1. In Salesforce Setup, navigate to Email > Organization-Wide Addresses and create the email address you want to use as the From address, or identify an existing one.
2. In Apex, query the OrgWideEmailAddress object to retrieve the ID of the desired email address. For example, query OrgWideEmailAddress where the Address field equals the address you want to use (such as 'support@yourcompany.com') and retrieve the Id of the first matching record.
3. Create a new instance of Messaging.SingleEmailMessage and call the setOrgWideEmailAddressId() method, passing in the ID retrieved in step 2.
4. Set the remaining email properties (recipient, subject, body) and call Messaging.sendEmail() to send the email.
5. If the OrgWideEmailAddress query returns no results, ensure the address has been created and verified in Setup under Email > Organization-Wide Addresses.