GST PRACTITIONER ELIGIBILITY

Any person who is a citizen of India, is not adjudged insolvent and is not convicted of imprisonment for 2 years or more can become a GST practitioner. The qualifications include: you should be CA, CS or Cost Accountant or a graduate or post graduate in commerce,law , banking or is a tax return preparer or a sales tax practitioner or a retired officer of the commercial tax department of any state. 

Yes, it is compulsory to get registered on GST site.