Adding funds to your PSN Wallet, which is used to purchase full-length retail games via digital means, or just simply Download Content for your favorite games, is a relatively painless task.

From your PS4 interface: Go to Settings > PSN > Log in, then select Fund Wallet. From here you're able to add funds with an accepted credit card or redeem a code.

From your browser: Log in to store.sonyentertainmentnetwork.com with your PSN account and click on the dollar sign to left of the check-out sign or alternatively find your account name and click on Add Wallet Funds. Via here you will be able to choose a payment method, such the credit card of your choosing or even a prepaid PlayStation Store card that you can purchase from big box retail outlets. Other payment methods include sending money from PayPal or your mobile device.

Please note that you may remove your credit card at any time from the account, for anyone who dislikes their credit information being readily accessible.