Document Info Records and Original Application Files 
When you use document management, you create document info records and you assign original application files to the document info records. Note the following:
Document info record (DIR): This is the master record in the SAP system that describes one or more original application files. It is the main object on which document management is based.
Original application file (original): This is a file that can be generated by any application, for example, Microsoft Office files, or graphic files such as JPF files or TIF drawings. You can assign one or more originals to a DIR.
In addition to the originals, the DIR contains all relevant data such as user responsible, classification information, object links, status information, and metadata, including the description.
When you create a DIR, you must specify the document type. You define the required document types in Customizing for Document Management, for example, you can define a document type for each relevant file extension. The document type contains different settings such as the status network and object types for which object links can be created.