On PS4:

If you received a PS4 key (12 digits, example ABCD-1234-XYZA) go to Playstation Store and select "Redeem codes" at the bottom of the menu. Once the key has been redeemed, select "Download" to start downloading the game.

For any other questions, please visit the Help section of the Playstation website:

https://support.us.playstation.com/

On Xbox One:

If you received a Xbox One key (25 digits, example ABCD123456EFGH7891IJKL234) On Xbox One, select Xbox Store > Browse games > Use a code. Once the code has been redeemed, the game will start downloading on your console.

For any other questions, please visit the Xbox Support section of the Xbox website:

https://support.xbox.com/en-US/browse/xbox-one