Warning: Make sure that the forwarding is set to email that is inside the Organization (Company)

Official Microsoft instructions: Turn on automatic forwarding in Outlook - Microsoft Support

*If you are using Outlook New or Outlook on the web (OWA) scroll below for instructions

Outlook Classic

1.  Search for Rules > Create rule
2. Choose Advanced Options...
   
3. On step one just press "Next"
   
4. You will get a warning that the rule will be applied to every message you receive. Press Yes.
   
5. Checkmark "redirect it to people or public group and then press on it in the bottom window
   
6. Search for user(s) you want the emails forwarded in the top left and then double click them from the list. Make sure they show up in "To" form.
   
7. Once done press Finish
   

Outlook New & Outlook on the web (OWA)

1. Go to setting on top right > Mail > Forwarding
   
2. Enable forwarding and make sure that "Keep a copy of forwarded messages" is turned on