How do you get hoopa in Pokemon X y?

You can't get Hoopa in Pokemon X and Y. Hoopa was introduced in Pokemon Omega Ruby and Alpha Sapphire.

Here's why:

* Game Versions: Hoopa's debut was in the Generation VI games Omega Ruby and Alpha Sapphire. It was not available in the original X and Y.

* Event Distribution: Hoopa was initially distributed through special events in Japan. Later, it became available through other event distributions globally.

If you want to get Hoopa, you'll need to play Pokemon Omega Ruby or Alpha Sapphire, or trade for it from someone who has obtained it through an event.