Hi Vijaykrishna,
You should check in declaration part, It's important declare each an every field serial order. and In the field catalog section take a variable and its increase the value for each an every fields options and pass the variable in COL_POS. and the the values put in all are caps like 'EBELN', 'I_FINAL'.
Ex-
DATA : C_POSTYPE i.
C_POS= C_POS + 1.
w_fldcat-fieldname = 'EBELN'.
w_fldcat-tabname = 'I_FINAL'.
w_fldcat-col_pos = C_POS.
w_fldcat-hotspot = 'X'.
w_fldcat-seltext_l = 'PO NO'.
w_fldcat-emphasize = 'C510'.
APPEND w_fldcat TO i_fldcat.
CLEAR : w_fldcat.
C_POS= C_POS+ 1.
w_fldcat-fieldname = 'EBELP'.
w_fldcat-tabname = 'I_FINAL'.
w_fldcat-col_pos = C_POS.
w_fldcat-hotspot = 'X'.
w_fldcat-seltext_l = 'PO Item'.
w_fldcat-emphasize = 'C501'.
APPEND w_fldcat TO i_fldcat.
CLEAR : w_fldcat.
C_POS= C_POS + 1.
w_fldcat-fieldname = 'MATNR'.
w_fldcat-tabname = 'I_FINAL'.
w_fldcat-col_pos = C_POS.
w_fldcat-emphasize = 'C511'.
w_fldcat-seltext_l = 'Material NO'.
APPEND w_fldcat TO i_fldcat.
CLEAR : w_fldcat.
Thanks