FMED_S_HEADER is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Entry document header structure" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_FMED_S_HEADER TYPE FMED_S_HEADER.
The FMED_S_HEADER table consists of various fields, each holding specific information or linking keys about Entry document header structure data available in SAP. These include DOCFAM (Document Family Number), EXT_DOCNR (External Number for Budget Entry Document), TECHORG (Original Application), VERSION (Budget version)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .