Registration as a GST Practitioner is mandatory if you intend to formally act as a practitioner to file returns and represent taxpayers on the GST portal. After submitting your application (Form PCT-01), the approval process by a tax officer typically takes up to 15 days, after which you will receive your GSTP ID and enrollment certificate. Additionally, you must pass a mandatory exam conducted by NACIN within two years of your enrollment to remain eligible to practice.