SAP IDoc (Intermediate Document) is a standardized data format used in SAP systems to facilitate the exchange of information between different systems, both SAP and non-SAP. It serves as a medium for electronic data interchange (EDI), enabling the seamless transmission of business documents such as orders, invoices, and delivery notes. IDocs are used for communication between SAP modules or between SAP and external systems, supporting both inbound and outbound data processing. They help automate and streamline business processes, ensuring efficient and error-free data transfer across the supply chain.