You'll be redirected to Roblox's gift cards page. Tap on Redeem, located at the very top of the page. Enter the empty Code field with your Roblox gift card's code, then tap Redeem to finish.

Learn how to redeem a Roblox gift card in detail A gift card, regardless of its format, can be done online on the game's website.

You can redeem a Roblox gift card by applying the balance to your account or by using it during the checkout process.