ゆうちょ通帳アプリ is a free mobile application developed by Japan Post Bank Co.Ltd. It is designed to provide convenient banking services for customers who have a general account with Japan Post Bank. With this app, users can perform a variety of functions including checking their account balance, reviewing transaction details, updating their address and phone number, and making various types of deposits and withdrawals. Users can also purchase and redeem investment trusts, switch to the comprehensive account type, and transfer funds to other financial institutions.

The app supports ATM deposits and withdrawals, as well as bill payments, including regular payments and tax payments. Users can also utilize biometric authentication for added security. The app allows for registration of up to two accounts under the same name, and users can log in using a four-digit passcode or biometric authentication.

Please note that the app requires certain personal information, such as account number, name in Kana, date of birth, and cash card PIN. It is important to keep the authentication code confidential and not share it with anyone. The app is available for iPhone users and can be downloaded for free, although data charges may apply.