If you registered for the Ultra Kalos Classic Online Competition and completed at least one match, you can now claim your participation prize of 50 Battle Points in Pokémon Ultra Sun and Ultra Moon. Just log in to the Pokémon Global Link (PGL) using the game that you used to participate in the Ultra Kalos Classic Online Competition and then click here.
To redeem the code in your game, select Mystery Gift from the main menu, then select Receive Gift, and then select Get with Code/Password and follow the prompts to enter your special code. Be sure to enter the code in your Pokémon Ultra Sun or Pokémon Ultra Moon game before July 30, 2018, at 23:59 UTC.
Visit the official Online Competitions page for Ultra Kalos Classic Online Competition player and Pokémon rankings.
Source: Pokémon Global Link