Let others send faxes through your Mac
You can use Printers & Scanners preferences to let other Mac users on your local network send faxes through a multifunction printer connected to your Mac. The other Mac computers must be using OS X 10.5 or later.
On your Mac, choose Apple menu > System Preferences, then click Printers & Scanners.
Select the multifunction printer in the list at the left.
Select “Share this printer on the network.”
Other users’ documents waiting to be faxed through your Mac are stored on your hard disk; that is, your Mac hosts the queue for the faxes.