1. Log into the portal (https://portal.office.com/) as the admin.
  2. From the landing site, go to "Admin" then, on the left-side admin panel, go to Exchange.
  3. Once you're in the Exchange Admin Center, select Recipients, and Mailboxes
  4. Then click the name of the user whose email you want to forward and select the Edit icon (little pencil).
  5. Now select Mailbox Features from the left and scroll down to the Mail Flow section, and click View details.
  6. In the delivery options, Check the box next to Enable Forwarding.
  7. Select the email address to forward to using the browse button.
  8. Now you can tell it whether to continue delivering email tot he original mailbox or not.
  9. Hit save and this should start forwarding new emails immediately.