You can register as a tax practitioner on GST website. Procedure to register is simple. You can read about eligibility and documents for GST practitioner registration.
As a GST practitioner you are not required to file any return.
But however if you are registered as a tax payer also then you need to file normal returns applicable to a tax payer.
GST practitioner registration is different from a normal GST registration.
If you are eligible to be registered as a normal tax payer, then you have to separately register as a tax payer and file required returns.