I haven't signed for the postal express yet, why is it displayed?

Don't worry, the postal courier showed the receipt, which means that the postal company or the corresponding courier point has collected it for you, which means that you signed for the courier on your behalf. When they arrange the express delivery, they will inform you to pick it up by text message or phone.

Extended data:

Postal service is a communication department managed by the state or directly engaged in delivering all kinds of mail (letters or articles), which has the characteristics of communicating officials, businessmen and people. Postal service is a productive force. For example, a "letter meeting" is a meeting to exchange views, focus on topics and handle affairs with the help of the national post. 1On March 20th, 896, Emperor Guangxu of Qing Dynasty memorialized Zhu Pi, officially approved the establishment of the General Post Office of Qing Dynasty, and China Modern Post was born.

References:

China Post, Baidu Encyclopedia