for all type work contract HSN code?
For Registration Use 00440410 for work contract
Refer
https://www.teachoo.com/gst/hsn-code/#gst_services
For Billing,Refer following excel file
Classification Scheme for Services under GST.xlsx
For Rates,Refer
https://www.teachoo.com/6339/1903/Tax-Rate-in-GST-on-Services/category/GST-Basics/