add-on needs to allow payments outside of US and Canada

I’m looking for some information about being able to use Authorize.Net add-on to allow more countries than just the US and Canada. According to’s site:

As long as your business is based in the United States, Canada, United Kingdom, Europe or Australia, you can accept international payments from anywhere in the world.

But I don’t know where to start. Perhaps this is better as a feature request, but any feedback is appreciated.