When a job fails, you have set to have it alert an operator.
For the operator setting, you can add multiple email address to the “E-mail name” field separated by semicolon.
Edit via script…
EXECUTE msdb.dbo.sp_update_operator @name = N'JobWatcher', @email_address = Nfirstname.lastname@example.org;email@example.com';
Note: There is a 100 character limit. It is set in the sysoperators table. DO NOT try to ALTER the email_address column. This will break the GUI.
SELECT * FROM sysoperators