BAPI_0050_HEADER_GET 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 "Header data for entry document" 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_BAPI_0050_HEADER_GET TYPE BAPI_0050_HEADER_GET.
The BAPI_0050_HEADER_GET table consists of various fields, each holding specific information or linking keys about Header data for entry document data available in SAP. These include DOC_YEAR (Document Year), DOCUMENT (Budget entry document number), VERSION (Budget version), DOCDATE (Document Date)... 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. .