Hi Meena,
It will applicable for all vendors, who has maintained with this withholding tax type. If you want to only for specific vendors, then you have below possibilities:
1. Maintain this code for only exemption vendors and for non-exemption vendors create a separate withholding code.
or
2. No need to maintain any exemption details in the w.h.type formula configuration. You have just maintained exemption details in the vendor master.
Regards,
Mukthar