Return file of GST

If you exclusively deal in goods that are wholly exempt from the levy of GST then no need to register for GST. However if not then 37 returns will have to be filed annually.

If sell of my goods is touching at 16 lakh annually. Is there need to take registration?

Compulsory registration is not required in your case as your turnover does not exceed Rs. 20 Lakhs. However if you want you can register voluntarily.

Ok if I selling my product through online marketplace?

Then compulsory registration is required under Section 24.

May I know about 37 returns annually In detail

1 return for outward supply in form GSTR-1 containing details of all outward supplies made during the month. 1 return for inward supplies in Form GSTR-2 containing details all the inward supplies received during the month. 1 monthly return for every month. So total 3 returns per month. 36 returns per year. In the end 1 annual return to sum it up all. Total 37 returns.

1 outward return, 1 inward. Its ok but what is 1 monthly return for every month?

Inward=Purchase ?
Outward= Sales?

Monthly return is in form GSTR-3 which includes finalization of outward supplies and inward supplies along with the payment of amount of tax.

My CA has taken the registration of GST. Can I cancel my registration?

You are selling goods via e commerce operator who are required to collect TCS under Section 52 of the CGST Act. Hence compulsory registration for you under Section 24. BTW you are not happy with GST or your CA??

No I m happy with my CA. If I m not selling goods via e commerce in this situation what should do? should I sustain my registration or can I cancel it?

If you are not selling goods through e commerce you are not liable for compulsory registration. On the positive side you don't have to do any compliance of filing returns, paying taxes, maintaining accounts and records. However on the negative side you won't get any input tax credit on GST paid to your suppliers, you won't be able to collect any GST from your clients, if your clients are also registered dealers then if they purchase goods from you they have to pay tax by reverse charge mechanism hence more compliance for them etc. So there are pros and cons of not registering in GST and ultimately you have to decide.

If I selling taxeble goods and my annual sell is less than 20 lakh. Will I have to take registration of GST?