Gst registration for service job

as per section 22 every person is required to obtain registration under cgst act in the state from where he make supply of goods or service or both....................

you will not be required to take registration in all 5 state if you are not maintaing any place of business there. you have to pay IGST In your case.

What is the type of service you are providing?

Plant erection, commissioning, and installation

Sir,

For the execution of the job, we need to purchase consumables and safety items and tools from the job site. can we avail the ITR on these purchases.

You will charge igst on your supplies if you are providing services from gujarat
And you are eligible to take credits.