BAPI_0050_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 "Header data for Entry document - Method Create" 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 TYPE BAPI_0050_HEADER.
The BAPI_0050_HEADER table consists of various fields, each holding specific information or linking keys about Header data for Entry document - Method Create data available in SAP. These include VERSION (Budget version), DOCDATE (Document Date), PSTNG_DATE (Posting Date in the Document), DOCTYPE (Budget entry document type)... 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. .