You need to add the shared fax printer to the client computers. It's pretty common for it to not show up with the add printer wizard.

On a Client Computer:
1. Go to Devices and Printers in the start menu
2. Choose Add a Network Printer
3. Likely it will not show up so choose "The Printer I want isn't listed."
4. Select a shared printer by name, type "\\YOUR_SERVER_NAME\\Fax"
e.g. mine would be \\luthraserver\fax

Sending the note would be the same as printing it. Print to the Fax printer and the wizard will pop up where you can specify a contact/phone number.