An image forming system has an image forming apparatus configured to function as a groupware terminal, and a groupware server of a groupware having a document database configured to store document data and attribute information corresponding to the document data, and an attribute database configured to store the attribute information. The image forming apparatus has a scan part configured to scan a paper document and to obtain document data, a setting part configured to set a certain attribute information of the document data obtained by the scan part, by referring to the attribute information stored in the attribute database, and a sending part configured to send to the groupware server the document data having the set attribute information. The groupware server stores the document data having the set attribute information, received from the sending part, in the document database.