Turn on automatic forwarding in Outlook on the web

You can automatically forward or redirect your email messages by setting up Inbox rules in Outlook on the web. This is useful if you want to read and respond to messages from another email account or when you want someone else to receive and respond to your email in your absence.

1. Go to outlook.office.com
2. At the top of the page, select Settings > View all Outlook settings.
3. Select Mail > Forwarding.
4. Do one of the following:
   To turn on forwarding, select Start forwarding, enter the forwarding email address and select Save.
   Note: Select the Keep a copy of forwarded messages check box if you want a copy of the original message to remain in your mailbox.
   To turn off forwarding, select Stop forwarding and select Save.

More resources

Alternatively you might be interested in giving another user read and send permissions on this mailbox.