This APP is a mobile application developed for printers, which can edit and print the contents of barcode printers. The APP includes fixed templates and custom editing templates. Fixed template can be edited content, custom template can be free to edit the print effect for printing. APP includes bar code, two-dimensional code, text, picture, time, table, graphics and other functions. The APP can be connected in three ways: USB, Bluetooth and WiFi. Aiming at the use of 4-inch bar code printer, this APP applies Bluetooth connection and transmission technology, so that the printer can collect the edited content on the APP and transmit it to the printer. At the same time, it supports network connection and USB physical connection. Interfaces basically cover the external interfaces of mobile phones. The APP also supports different paper types: label paper, ticket paper, black label paper, etc.