Follow these given below steps to print Extra heading and No. on bill format:---
1.Go to MASTER => MARGSETUP => SELF FORMAT => Select invoice format-98 [DMP]/99[GUI]
2.Feed format name => BILL FORMAT =>HEADER=> Press F1 key For print extra heading => Search “S.T.”=> Select option of “PARTY EXTRA S.T. HEADING NAME”=> Press ENTER key.
3.Now Press F3 key for apply command => Use command (SL_EXTHED,12)

4.Press F1 key For print extra heading No. => Search “S.T.”=> Select option of “PARTY EXTRA S.T. NO.”=> Press ENTER key.

5.Now Press F3 key for apply command => Use command (SL_EXTNO,35)=> Press CTRL+W=> Click on SAVE => Press ESC key to EXIT.