The au PAY Gift Card is a prepaid card that allows you to add funds to your au PAY balance, enabling cashless payments at over 1 million participating stores across Japan, both in physical locations and online.
Download the au PAY app from the App Store or Google Play. Open the app and set up your account. You don't need to be an au mobile user to register. On the home screen, tap "チャージ" (Charge). Select "au PAY ギフトカード" (au PAY Gift Card) as your charge method. Scan the QR code on the back of the card, or tap "コード番号を手入力" to enter the 16-digit code manually. Tap "コードを確定する" (Confirm Code) to add the balance to your au PAY account. To pay in stores, open the app, tap "コード支払い" (Code Payment), and show the barcode or QR code to the cashier.