
You can tell what region the Pokémon is from by looking at its PokéDex entry.
If the Pokémon you want to breed is genderless, then you will need to breed it with a Ditto. This means they must be the same species or share an Egg Group, and are opposite genders.
The two Pokémon must be able to breed normally with each other. There are several popular trading sites online that can make this a fairly simple process, such as PokéBay and Reddit's Pokémon Trading subreddit.
The easiest way to get a Pokémon from another region is to trade with someone. This breeding method, also known as the Masuda method, is only available in Pokémon Diamond, Pearl, Platinum, HeartGold, SoulSilver, Black, White, Black 2, White 2, X, and Y, Omega Ruby, Alpha Sapphire, Sun, Moon, Ultra Sun and Ultra Moon. Make sure to obtain the Pokémon that you want to get a Shiny version of. For example, if you live in the USA, obtain a Pokémon from Japan or Europe. The key to breeding a Shiny Pokémon is to breed Pokémon from two different regions.
Obtain a Pokémon from another real-life region.