You can redeem a PlayStation Network key either online or directly on your console.
Website Activation
1 .Log in to your Playstation account by clicking the Sign In button in the upper-right corner.
2 .Click on the icon to open a drop-down menu.
3 .Select Redeem Code from the menu.
4 .Enter your key on the redemption screen, ensuring accuracy.
5 .Confirm the activation on the confirmation screen.
Console Activation (PlayStation 4)
1 .Log in to your PlayStation Network account.
2 .Navigate to the PlayStation Store.
3. Select Redeem Codes from the navigation bar.
4 .Enter your key in the provided field and confirm.