1. First, log in to the telecom business hall, search for "China Telecom" on Baidu, and click the website with "official website" at the end of the website to enter official website. 2. After entering the official website of China Telecom, select "Login" at the top to enter the login interface of mobile phone number. 3. Enter your mobile phone number and login password in the login interface (if no login password has been set, you can choose your mobile phone to send a temporary random password) and enter the verification code to enter. 5. After logging in successfully, select "My Telecom Account" in the upper right corner of the page and enter the management center. 6. After entering my account page, select the "service customization" menu and click the "credit service" column. 7. Drop down the menu under the credit limit and adjust it from "No Credit Limit" to "1 yuan". According to the access period and credit authority of each telecom mobile phone number, the overdraft consumption limit will be different. And save the settings. For more service offers, click on the "official website" customer service 219 below to answer your questions.