How to activate the From field in Outlook.

Note: This will only work if you have access to a Shared Mailbox. 

2: In the New Email, click on the tab called Options, then under Show Fields you will see From. 

3: Click on From and you will now see it listed above To. This will default to your work email address. 

4: To add a shared mail click on the drop down in From and select Other Email Address.

5: Next you will get a pop up of the shared mailbox you want to add. You can also click on From and it will bring up the Global Address List, select the shared mailbox and hit OK and then OK again. 

Now you will have access to send from that shared mailbox by clicking the drop down in From when creating a new email.