PF and ESI Certificate - GST registration in Bihar, but they are working in Karnataka now

Madam/Sir, A proprietorship firm, the nature of business is contract work. The person is a citizen of Bihar. He has taken GST registration in Bihar, but they are working in Karnataka now. Now contractor asking for the PF & ESI Certificate. where do they need to register for PF & ESI? in Karnataka or in Bihar?
Please guide me

Dear Member, Obtaining PF /ESI code number is not limited by territorial jurisdiction so One may take PF and ESI code reflecting the particulars of current contract in the State Of Karnataka also but it would be advisable that he may may attempt to obtain the PF/ESI code number for his firm from the regional office of his area in Bihar. It may be creating conveniences on him later.