A method, device and system for transmitting information. A first user device acquires input information of a first user in an input box, displays information in a current input line in a corresponding biggest available font on the basis that a total display width of the information in the current input line is less than or equal to a line display width of the input box, and sends, when acquiring an information sending operation of the first user, the information in the input box to a second user device via a network device, and the second user device receives and displays the information in the input box. A layout operation is performed in the corresponding biggest available font on the basis that the total display width of the information in the current input line is less than or equal to the line display width of the input box.