As per Sub-section 68 of Section 2 of CGST Act 2017, ” means any treatment or process undertaken by a person on goods belonging to another registered person and the expression “job worker” shall be construed accordingly” meaning that it would amount to supply if the job worker adds any materials during the process or treatment. This is a major change in the job work process compared to erstwhile Central Excise Act.
india-gst.in 