Hi,
From Outlook client side, you may try to create inbox rules to automatically add the shared mailbox in the Cc field when sending emails.
From Exchange side, you may consider to create transport rule to achieve the goal. See the following reference for more details:
https://www.oxfordsbsguy.com/2013/03/09/how-to-copy-incoming-or-outgoing-emails-to-another-mailbox-in-exchange-2007-or-2010/
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
To know more about this, you can also post to the dedicated
Exchange forum.
Regards,
Steve Fan
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