Well, which platform that you prefer in playing the game? Because Genshin is currently available in many platforms.
If you’re playing on an Android phone, then you can search the Google Play Store for the game.
If you’re playing on iPhones, then go check the App Store.
If you’re playing on the PS4/PS5, then search it at the Playstation Store.
If you’re playing on PC, then you can go to either Genshin’s website to download the client, or you can download it from the Epic Store instead.