rate of GST

we do supply of men to Textile industries all around India on contract or Job work basis. we support by sending man power supply to do job work in their premises. The nature of work is textile processing mostly yarn and fabric processing. we do not use any machinery from our side. just our

men working in their premises on job work basis or piece rate basis. i want to know what rate of tax i have to apply and the HSN Code needed to print in our invoice