An image forming apparatus, comprising: a document reading unit for generating reading data by reading a document; an operation unit including a display unit for displaying various setting screens, including a program selection screen and a box data selection screen, used to set and input function settings of various functions executable in the image forming apparatus, the function settings being a combination of various setting items of the function and set values for the setting items, and adapted to receive the function settings set and input on the setting screens displayed on the display unit as input data; a plurality of document boxes for storing the reading data, generated by the document reading unit, as box data, each document box having identification information; a box data receiver for receiving box data selected on the box data selection screen to select the box data stored in one of the plurality of document boxes; and a display controller for causing the display unit to display the various setting screens; characterized in that the image forming apparatus further comprising: a program storage for storing a plurality of programs each with at least one function setting, and each in correspondence with the identification information of one of the plurality of document boxes; a program receiver for receiving a program selected on the program selection screen to select the program stored in the program storage; and an execution controller for operating a function to be operated with function settings provided in the selected program; wherein the execution controller is adapted to: cause the display unit to display the box data stored in the document box identified by the identification information corresponding to the received program on the box data selection screen when the program is received by the program receiver; and handle the received box data as the input data to be processed by the execution of the function and operate the function to be operated with the function settings provided in the received program after the box data selected on the displayed box data selection screen is received by the box data receiver. a document reading unit for generating reading data by reading a document; an operation unit including a display unit for displaying various setting screens, including a program selection screen and a box data selection screen, used to set and input function settings of various functions executable in the image forming apparatus, the function settings being a combination of various setting items of the function and set values for the setting items, and adapted to receive the function settings set and input on the setting screens displayed on the display unit as input data; a plurality of document boxes for storing the reading data, generated by the document reading unit, as box data, each document box having identification information; a box data receiver for receiving box data selected on the box data selection screen to select the box data stored in one of the plurality of document boxes; and a display controller for causing the display unit to display the various setting screens; characterized in that the image forming apparatus further comprising: a program storage for storing a plurality of programs each with at least one function setting, and each in correspondence with the identification information of one of the plurality of document boxes; a program receiver for receiving a program selected on the program selection screen to select the program stored in the program storage; and an execution controller for operating a function to be operated with function settings provided in the selected program; a program storage for storing a plurality of programs each with at least one function setting, and each in correspondence with the identification information of one of the plurality of document boxes; a program receiver for receiving a program selected on the program selection screen to select the program stored in the program storage; and an execution controller for operating a function to be operated with function settings provided in the selected program; wherein the execution controller is adapted to: cause the display unit to display the box data stored in the document box identified by the identification information corresponding to the received program on the box data selection screen when the program is received by the program receiver; and handle the received box data as the input data to be processed by the execution of the function and operate the function to be operated with the function settings provided in the received program after the box data selected on the displayed box data selection screen is received by the box data receiver. cause the display unit to display the box data stored in the document box identified by the identification information corresponding to the received program on the box data selection screen when the program is received by the program receiver; and handle the received box data as the input data to be processed by the execution of the function and operate the function to be operated with the function settings provided in the received program after the box data selected on the displayed box data selection screen is received by the box data receiver.