Presuming u mean a ExchangeOutlook setup?
To use Ex u will need 3rd party sw. Like a add in for exchange. If u have spare analogue lines however u can just put modemfax cards into the pcs. Connect those up to a spare line. U can even make RJ11 plug into RJ45. And use the fax wizard in 2k XP.
B careful of third party sw. Make sure it is able to send a confirmation report. Not many of them do and it’s about the most important thing to the user to be certain the fax was sent.
Aside from all that, ditch faxes and use email!