First of all, the option to redeem a Roblox gift card cannot be done within the game. You have to do it on the official Roblox Game Card Redemption Page. Once you are on the Roblox Game Card Redemption Page, you will need to login to your Roblox account. This ensures that the credit will be applied your account.
You will now need to convert the Roblox credit into Robux so that the currency can be used within the game. Miraculously, the link to convert Roblox credit into Robux isn't listed or linked to anywhere on the Roblox Game Card Redemption Page, so it's no wonder that the whole process to convert a Roblox gift card into Robux is overly complicated ...
Roblox Gift Cards are the easiest way to load up on credit for Robux or a Premium subscription. Includes a bonus Meganoob Pal for a limited time.
Please note that Amazon Digital Gift Cards only grant Robux and cannot be used toward a Premium subscription.
Redeem any gift card to obtain a free virtual item exclusive to that month.