Hi Nikhil,
To find the BADI you should know the BAPI, I hope you have BAPI. Open you BAPI in SE37 put external breakpoint at first statement, and execute.
Once the debugging is started, Press Shift+F9.
Give Class Name: CL_EXITHANDLER
Method Name: GET_INSTANCE
Press F8. If your BAPI has BADI it will take to get_instance method. In this method check method parameter exit_name, you will find a BADI name starting with BADI_xxx.
Creating Implementation for BADI.
Go to transaction SE19 and provide BADI name and click on implementation.
Provide Implementation name and press continue.
You will get list of methods. Implement the method that you want to according to your requirement and write your logic here.
