G2A is a global transaction ecosystem and financial technology company which connects the entire G2A Ecosystem with international and local payment methods. The focal point of this ecosystem is G2A Marketplace, the world’s largest marketplace for digital products.
What you do is buy your key, wait for it to be emailed to you, then head to the relevant platform: Epic Games Store, Steam, Uplay, etc, log in and select the option to activate a game. You paste in your key and then download the game files from the platform’s servers.
G2A adds steps to prevent fraud. Sellers have to verify their social media details and phone numbers, and are limited to 10 transactions before having to provide extra verification. Its aim is to prevent dodgy sellers from scamming buyers with non-working game codes.