PURPOSE: To reduce user's operation load and to simplify operation by automatically forming menu guidance with expression to be easily operated by the user in each generation of data in the case of converting document data formed by a host computer into mail data.

CONSTITUTION: A guidance menu is automatically set up in a menu file 18 and mail data 19 are formed in each destination and in each document identification code. When the user requests menu display from a terminal, a destination belonging to the terminal is judged from the menu file 18 and the corresponding menu guidance is displayed to extract the menu data 19. When the user operates the terminal in accordance with the menu guidance, the mail data concerned are outputted from a printer 10.