I may be having a very blond moment but I have been looking for the answer on how to do this. I keep seeing reference to a Settings folder which for my up to date PS and ACR I don't have. Please put me out of my frustration and tell me how and where I can add ACR presets that I have.
The folder should be in your User Library
/Users/UserName/Library/Application Support/Adobe/CameraRaw/Settings
To easily see your user library, in the Finder Go menu, press the Option key and then you should see the word Library