That's certainly not the case in the majority of Europe, Australia, New Zealand, East Africa, West Africa, South Africa, PNG, Fiji, Philippines, South Asia and South East Asia. Really it's mostly just America and Canada that use American.
American forms are definitely dominant in the Philippines, even in an official capacity. I can't comment on Africa, but I would also characterize SEA as American-leaning in the wild; en-gb dominates in education but largely illusory. Elsethread the same claim is made of the "majority of Europe".
I could cite many sources but https://en.wikipedia.org/wiki/American_and_British_English_s... provides a simple view.