Do you have a multifunction printer attached? If so when you go to print the letter choose Print Preview instead of Print and when you then hit Print it should bring up the Printer Options including attached fax
This is yet another area of do you want cheap vs high quality. I used to use the Brooktrout card. Great card but with limitations.
Sandeep recommended Mainepine and helped to install it. You don't have to research it. $600 board vs a $30 modem. And, support is free for life. At least it was when I purchased it. And, support is very good.