hi Raju
I understand your concern . The program /SAPSRM/OFFLINEAPPROVALSEND is actually a sample released by SAP and if there is no custom requirment you could just use the program AS IS .
however since you would like to change , Please copy the standard program and make changes in program or BADI which the program uses .. BBP_OFFLINE_APP_BADI
it basically uses this BADI and will automatically modify the inputs .
You need to basically debug and sit with a technical consultant to understand where to do these changes . You can incorporate a adobe form as well for approval or can go with the buttons for each line depending on how the client requirment is .
After the changes are done . Stop the standard batch job for this program and get a new batch job to run for your custom program .
Refer link below
Regards
Vinita