An image forming apparatus which configures a printing system includes an application server which has a function of editing and storing document data, and provides the document data in response to a request; the image forming apparatus having a plurality of functions including a printing function; a data generation apparatus which generates, from the document data, print data printable by the image forming apparatus; and a storage apparatus which stores data having undergone processing by the image forming apparatus, the apparatuses being communicable with each other via a network, comprising: recording unit configured to record, as difference data, a setting difference upon setting change of print data; and transmission unit configured to execute processing for the print data, and transmitting a completion notification of the processing together with the difference data.