CMA Final · Indirect Tax Laws and Practice

Walkthrough of GSTN Portal: formula sheet

Key formulas

Part A of Form GST REG-01: Legal name (as per PAN) + PAN + State/UT + mobile (OTP) + email (OTP) → TRN; Part A is only the basic details stage. A TRN is not a registration and gives no GSTIN.
Part B of Form GST REG-01: Login with TRN + OTP → full details + documents + verification → ARN; The ARN is generated on successful submission of Part B after verification by DSC, e-signature or EVC, as applicable.
TRN validity: TRN is valid for a limited period (currently 15 days per portal practice); This period is not a statutory figure in the Act or Rules. If Part B is not completed in time, you restart from Part A. Verify the current period against the portal help before the exam.
Registration certificate: Form GST REG-06; Issued on approval. The 15-digit GSTIN is allotted on grant.
Notice and reply: Query: Form GST REG-03; Reply: Form GST REG-04; Used when the officer seeks clarification or documents on the application.
GSTIN structure: 2-digit state code + 10-character PAN + 1 entity number + Z + 1 check digit = 15 characters; The 14th character is by default Z.

The GST portal is the common online platform for registration, returns, payments, refunds and notices.
Registration is applied for online through the portal.
Learn the registration steps as a fixed sequence.
Know which acknowledgement or number is generated after submission of the application.
Keep identity, business and address proofs ready before applying.
Know who processes the application after it is submitted.
Link portal steps to the legal registration rules in your CGST notes.
Check the latest portal process, since screens and procedures can change.
Practise identifying the next step in a scenario question.
Do not mix up the portal's role with the legal liability to register.

Treating the TRN as proof of registration. Fix: Remember that TRN is only a temporary reference. Registration exists only after grant, with GSTIN and REG-06.
Saying GSTN grants registration or assesses tax. Fix: GSTN is an IT service provider. Registration is granted by the proper officer of the tax administration.

Learn the chain Part A → TRN → Part B → ARN → REG-06. Most MCQs test one link of it.
Write who does what: GSTN provides technology, the proper officer decides on registration.
In case questions, tell the person the next step, not just the stage they are at.
Check form numbers and time limits against the current rules and portal before the exam, as procedures are updated from time to time.