Send email from a different address in Outlook 2013
Configure Outlook 2013 so that you can send email from a different email address as follows:
First make sure the From field is visible: Click the New Email button at the top-left corner of the window. Click the Options tab at the top of the window. Click the From button in the Show Fields section. You should now see a From option at the top of the message section.
You can now select: "From other email address" in the From field when sending a new message. Type in the email address you want to send from!