This page will tell you how to redeem each code based on the format tag in the title of the product.
Most UV Codes will redeem at VUDU - https://www.vudu.com/content/redeem.html
Some codes must be redeemed elsewhere, which wil be noted in the email with the code under the redemption information.
For codes that are marked as iTunes ONLY - Open iTunes and go to “iTunes Store”. Select “Movies” and click “Redeem” on the right hand side. Enter your code and click Redeem.
Disney codes can be redeemed here - https://redeemdigitalmovie.com/