*&---------------------------------------------------------------*
*& Report  ZTEST_SEARCHHELP_ITAB
*&
*&---------------------------------------------------------------*
*& This report is to populate F4 help for custom fields
*&
*&---------------------------------------------------------------*

REPORT  ztest_searchhelp_itab.

*******************************************************************
*        TYPES DECLARATION                                        *
*******************************************************************
TYPES: BEGIN OF ty_mara,
       matnr TYPE mara-matnr,
       mtart TYPE mara-mtart,
       END OF ty_mara.

*******************************************************************
*        INTERNAL TABLE AND WORKAREA  DECLARATION                 *
*******************************************************************
DATA : it_mara TYPE TABLE OF ty_mara,
       wa_mara TYPE ty_mara.

*******************************************************************
*      PARAMETERS DECLARATION                                     *
*******************************************************************

PARAMETERS p_matnr TYPE ty_mara-matnr.

*******************************************************************
*    SELECTION SCREEN FOR VALUE REQUEST                           *
*******************************************************************

AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_matnr.

*******************************************************************
*    SELECT QUIRES FOR CUSTOM FIELDS                              *
*******************************************************************

SELECT matnr mtart FROM mara INTO TABLE it_mara UP TO 10 ROWS.

*******************************************************************
*      FUNCTION MODULE TO POPULATE F4 HELP                        *
*******************************************************************

  CALL FUNCTION 'F4IF_INT_TABLE_VALUE_REQUEST'
    EXPORTING
      retfield    = 'MATNR'
      dynpprog    = sy-repid
      dynpnr      = sy-dynnr
      dynprofield = 'P_MATNR'
      value_org   = 'S'
    TABLES
      value_tab   = it_mara. 

Click on F4 Help.