If you're in the US you can get a code at Gamestop from the Pokémon Pass app. In Canada, Australia and New Zealand you can get a code by visiting EB Games. Germany and Italy players can get a code through Gamestop's website. If you're in France then you can use Micromania's website and finally, those of you in Belgium and the Netherlands can get a code through GameMania's store.
Notably the event is currently not available in the UK, so unfortunately Pokémon fans here are out of luck for now. The event is live now and runs until the 19th of March, so you have awhile to get your hands on this special Pokémon. Details of the Toxtricity are as follows:
Ability: Punk Rock
Held Item: Throat Spray
- Sludge Wave
- Rising Voltage