To support efficient document registration processing in a network document management system comprising a digital composite machine, a document management server, and a document management client connected mutually via a network.

A folder keyword is set for each folder on a document management client to be stored in a document management server. In registration of image data acquired by scanning from the digital composite machine to the document management server as a document, text data extracted from the image data in scanning the image data and a folder candidate as a document registration destination is detected from the folder keyword stored in the document management server, and the folder information is displayed on the digital composite machine.