A Letter of Authorization for GST is an important document to share power. What's the Right Way to Structure a GST Authority Letter?A tax information authorization gives that person the legal right to review some confidential taxpayer information. A comprehensive guide on drafting a Letter of Authorization for GST, its compliance needs, and the roles of an Authorized Signatory. Step 1: Visit the GST portal and go to 'Services' > 'Registration' > 'New Registration'. Letter of authority authorizing for signing the application and related documents for GST. How can I register with GST? Call Letter for Night Watchman cum Sweeper for Tamil Nadu Sales Tax Appellate Tribunal - Click Here. The supplier is responsible for ensuring the certificate is properly completed (i.e.