Follow these steps to redeem your IMVU Prepaid Card:

  1. Sign in to your IMVU account in your browser
  2. Go to the IMVU Gift Cards page
  3. Enter the IMVU Prepaid Card which you can find under My Withdrawals by clicking on "Show Code"
  4. The balance has now been added to your IMVU account

Note: You can find the official instructions here.