Posting the phone number on the window of the house is disguised propaganda. Sticking the phone number on the window of the house can make customers get product information in time and effectively, which is publicity. The telephone number is the number set by the telephone management department for the telephone. The designated number set by enterprises, organizations, factories, mines and institutions for internal communication such as fixed telephones or mobile phones is generally 4-8 digits. It is also equivalent to the number and name of each mobile phone.