Setup and Verify the Organization-Wide Email Addresses
Setup Organization-Wide Email Addresses
In Setup, search for Organization-Wide Addresses.
Click on Add and fill in the fields.
Make sure to Allow All Profiles to Use this From Address.
You will get this warning after you click Save.
Verify Organization-Wide Email Addresses
When you initially set up the org-wide email, it sends a verification email to the email address. There is a link in the email sent to the org-wide email address, that once clicked, verifies the address.
Then, to double-check, the Admin can log in to http://salesforce.com, and under Setup | Administration Setup | Email Administration | Org Wide Email Addresses, the status will be set to "Verified." the above links are useful when you want to do through Apex.