Roblox gift cards are branded digital or physical “Cards” that allow users to redeem Credits (account balance) or Robux (the platform’s virtual currency). These credits or Robux can be used within Roblox’s platform to purchase items, avatar upgrades, game passes, or subscriptions (e.g. Roblox Premium) subject to availability.

Roblox gift cards / Robux are redeemed at roblox.com/redeem Once redeemed, the Robux is added to your Roblox account

https://en.help.roblox.com/hc/en-us/articles/15062225302804-U-S-TERMS-AND-CONDITIONS-FOR-ROBLOX-GIFT-CARDS <P> Important reminder Robux is tied to the Roblox account, not the device