invoice

Yes, GST applicable. It is a mere consideration for supplying manpower that has been bifurcated into PF ESI; Thus needs to be part of transaction value
As per Sec 15, transaction value for the purpose of levy of GST is total consideration including taxes, duties levied under other statue except taxes payable under CGST Act, IGST Act and UTGST/SGST Act. So GST payable on EPF /ESI also.