An Intermediate Document (IDoc), as the name suggests, is an intermediate document format for electronic data exchange between SAP application-based files and files from other external data applications. It is a standard data structure for programs written for two different applications to make it feasible to be processed in any application.
It is common in large organizations and enterprises for the physical distribution of computers to be geographically distant from the main database and may be using different storage software, hardware and operating systems. The Intermediate Document, IDoc, prevents the conversion of data formats and loss of important information by encapsulating the data file. IDocs are also used for non-server communication between workstations whereby the self-contained text file can be transferred between computers without having to connect with the central database.