BAPILAYIT 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 "BAPI communication structure: layout area items" 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_BAPILAYIT TYPE BAPILAYIT.
The BAPILAYIT table consists of various fields, each holding specific information or linking keys about BAPI communication structure: layout area items data available in SAP. These include AREA (Layout area number), ITEM (Identifier for layout area item), MATERIAL (Material Number), UNIT (Unit of Measure for Display)... 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. .