To redeem a Fortnite gift card on PS4, follow these steps:
1. Open the PlayStation Store on your PS4. You can find it on the home screen or in the Library section.
2. Scroll down and select the "Redeem Codes" option.
3. Enter the code from your Fortnite gift card using the on-screen keyboard. Make sure to enter it accurately.
4. Select "Continue" to proceed with the redemption process.
5. Once the code is verified, you will be prompted to confirm the redemption. Select "Confirm" to finalize it.
6. If successful, you will receive a confirmation message with details on what content or V-Bucks were added to your Fortnite account.
It's worth noting that Fortnite gift cards can be used to purchase V-Bucks, in-game currency for Fortnite, which allows you to unlock various cosmetic items, Battle Passes, and more.