Visit https://shop.garena.my/.
Log in to your Garena account.
Select the game you want to top up (for example, Free Fire, Call of Duty: Mobile Garena, Arena of Valor, etc.).
Select Garena Voucher or Garena Prepaid Card as your payment method.
Enter the Serial Number and Voucher Code/PIN (Secret Code) you received.
Click “Redeem” or “Confirm.”
Once successful, Garena Shells will be credited to your account or automatically converted into the selected in-game currency.