REMINDER: You need a PSN Singapore account to redeem purchases. For instructions on how to create one, please click here.
Via PSN Website
1. Log in to the PSN Website. Click on your profile at the top right of the screen and select "Redeem Code".
2. Enter the PSN Code and click "Next".
3. Your current balance and the voucher amount will be displayed. Confirm the details and select "Add Funds".
4. The confirmation page will appear and the amount will be automatically added to your wallet.
More information regarding PSN Playstation Card vouchers can be seen here.