I'm going to sell a CNC Machine & will include a lic. ver. of Mach 3.   How do I send the buyer the settings I have made to Mach 3 ?

Just send the xml file for the profile you are using, as an example if you have NOT made a custom profile and you are using Mill then look in the Mach3 folder and you will see Mach3Mill.xml. That is what all your settings are stored in. You my also need to send your macros if you have modified or made custom ones.
Hood