A client apparatus transmits to a server apparatus email information including destination email addresses of an email and information about a first file selected as a file to be attached, receives from the server apparatus at least one storage destination which is accessible to all users corresponding to the destination email addresses and in which a second file relating to the first file is stored as at least one storage destination candidate for the first file, displays the received storage destination candidate on a display, stores the first file in a storage destination corresponding to a storage destination candidate selected by a user from the displayed at least one storage destination candidate, and transmits to the destination email addresses an email including a link to the stored first file.