This is the 139 mailbox bill delivery service for sending short messages. With this service, the system will automatically send the phone bill to the 139 mailbox under the user's mobile phone number every month, so that you can easily know the consumption of the mobile phone, which is completely free and environmentally friendly. Parents can use it with confidence. You can open the website mail. 10086.cn on your computer or mobile phone, enter your account number and password (the account number is your mobile phone number, and you can log in by SMS for the first time), and enter "service mail-mobile phone bill" in your inbox to view the bill details, as shown in the figure. I hope I can help you!