Hi Mansur,
It is Simple.
After opening file with command OPEN DATA SET...
Before transferring the actual selected data to the file, transfer header information to the file.
Data: l_header type string.
l_header = 'Sample Header'.
open dataset ......
* set header to the file
transfer l_header to file.
* transfer data
loop at itab.
* transfer selected data
endloop.
close dataset.
Reward if helpful.
Regards,
Vasu Gunuputi.