There are many ways to find out the BADI .
method 1:
1. Find the package name for any transaction, hope you know this procedure.
2. Go to Object navigator SE80 transaction code, give package name and display, in the enhancement options you can find the BADI for the particular transaction.
method 2:
3. Go se24 class builder,give the class name CL_EXITHANDLER,There you can see call method GET_INSTANCES,Place the breakpoint,and come back.
4. Now you can go to any transaction,before the screen is displayed you will get the list of BADI.
For implement the particular BADI go to the transaction SE19.
5. We can use multiple implementation for the particular BADI,provide some implementation name,
and do whatever you want.
Regards.
RV Karthikeyan.