Click on Settings.
Click View all Outlook settings.
Click Mail > Sync email > Other email accounts.
Enter your account information, see example below.
Make sure to tick Manually configure account …
Fill in the blanks, see example below.
Make sure to select POP/SMTP connection settings.
DO NOT check Leave a copy of messages on the server unless you want to manually delete emails from company webmail.
Note: If you leave a copy and forgot to clear your company webmail, no new emails can come in when the quota is reached.
That’s it. Your company emails will now appear in Outlook.com.