Hello Naresh,
When you use PNP LDB, you can use appropriate Report Category which has WERKS as part of standard LDB selection screen. You can enter your Personnel Area values in that parameter. This would save you from creating custom Selection Screen with PERNR & WERKS.
I am stressing you to use selection screen values from Report category as much as possible. This would make LDB performance better.
You can use Report Category = "PSSPCDOC". This would provide a selection screen with PERNR and WERKS. So whenever you use GET PERNR event, employee data would be fetched based on the WERKS that you enter over here.