Sign in to Outlook on the Web via https://outlook.office.com.
At the top corner of the page, select the Settings gear
Use the search or View all Outlook settings to go to Mail, then Forwarding.
Select Start forwarding and enter the email address you want to forward to. You can also elect to Keep a copy of forwarded messages. Click Save.
Follow steps 1-4 above, then select Stop forwarding.
If you don't see the Forwarding tab under Accounts, forwarding may not be available for your account. You may be able to set up forwarding using Inbox rules. For more information, see Use rules in Outlook Web App to automatically forward messages to another account.
If you keep a copy of forwarded messages, you should check your Outlook Web App account regularly to make sure you haven't exceeded your mailbox size limit (1 TB). If the size limit is exceeded new messages may not be forwarded.