1. Postal code is a coding method that a country or region divides the whole country in order to realize the automation of mail sorting and the digitalization of postal network, and speed up the delivery of mail. Postal coding system has become one of the standards to measure a country's communication technology and postal service level.

2. Postal code usually consists of Arabic numerals, which represents a special code of the post office that delivers mail, and is also the code of communication between residents and units within the delivery range of the post office.

3. Postal code is a special code for postal communication to realize mail sorting, and it is a necessary tool to realize postal modernization. The ultimate goal is to improve the speed and accuracy of letters in the process of delivery. Therefore, it is necessary to specify the postal code when delivering letters and parcels. In order to realize the automation of mail sorting and the digitalization of postal network and speed up mail delivery.