How to retrieve your UID and server:
Open Genshin Impact;
Your UID is displayed in the bottom right corner of the screen;
Your server (America, Europe, Asia, or TW/HK/MO) is determined automatically based on your UID;
How to redeem:
Open the Genshin Impact top up page;
Choose the Genesis Crystal package;
Select a payment method;
Enter your UID and select your Server;
Complete the payment;
Wait for the crystals to appear in your account;
If missing, restart the game.