Aside from size limitations shipping International is no different than shipping domestic. Box it up, take it to shipping location. That's it.
Well, not really! What about import duties, broker's fees (when they get involved) and other issues, such as...
I sold a Peugeot to a fellow in Australia years ago. When the bike arrived there, it was put into a 30 day quarantine after being professionally cleaned. The customs people deemed the bike to be dirty (it wasn't) and insisted on the professional hosing down, followed by the quarantine. The cleaning cost the buyer $200 Australian.
I was horrified about this and asked the buyer what I could do. He said it was all OK and not to worry. Anyway...
The point is, shipping of any kind, can introduce some interesting problems. Other than that, I have sent a lot of bicycles all over the world and that was the only strange thing that happened.