1. After opening the mobile phone client of 139 mailbox, if the mobile phone is currently using the mobile data network and "password-free direct login" has been turned on, you can click "Quick Login" on the right side of 139 mailbox and click "Confirm Login" according to the page prompts to log in.

2. If the mobile phone uses the mobile data network, the mode of "one-click login for local phone number" will appear at the bottom of the page. Click "one-click login for local phone number" on the login page.

3. SIM card login function of mobile phone. Enter the mobile phone number, and the mobile phone will receive a login request. Enter the correct password to log in to the 139 mailbox.

4. Enter the mobile phone number/alias/mobile authentication number in the account field, enter the password in the password field, and then click Login.