TTEPDT_HEADER_DATA 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 "Document header" 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_TTEPDT_HEADER_DATA TYPE TTEPDT_HEADER_DATA.
The TTEPDT_HEADER_DATA table consists of various fields, each holding specific information or linking keys about Document header data available in SAP. These include PROCESSINGMODE (Processing Mode), TRACEMODE (TTE Trace Mode), TTESESSIONID (Session ID), TEXTOUTPUT (Text Output)... 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. .