-You go to the TCG Live web site: https://tcg.pokemon.com/en-gb/tcgl/
See Also
Pokémon Diamond cheats: Full cheat codes list and how to use themPokémon Scarlet and Violet cheats: How to get infinite money and duplicate itemsEarning the Defender Bonus — Pokémon GO Help CenterIn the main menu select "TCG Live", then select "Redeem Code". Make sure you have login in the site with your game account to be able to enter the code and recive the the packs, etc. ingame.
-You can also redeem dorectly in the game app:
Login the TCG Live > select Shop button > select the Redeem tab > enter the code or scan it.
