Indirect Tax Laws and Practice · Walkthrough of GSTN Portal

GST Portal Overview and New Registration Process

Updated 11 October 2026 · Fact-checked

GSTN is the company that runs the common GST portal, which links taxpayers, tax officers and banks. To register, you submit Part A of Form GST REG-01 (legal name, PAN, State/UT, mobile, email) and get a TRN. You then fill Part B with details and documents, and on successful submission after verification you receive an ARN.

Understand GST Portal Overview and Registration Process

The GST portal (www.gst.gov.in) is the single online platform for GST. Taxpayers use it to register, file returns, pay tax, claim refunds and track applications. Tax officers of the Centre and the States use the same system to process these applications. This is why GST is called a common, technology-driven system.

GSTN (Goods and Services Tax Network) is a non-profit, non-government company set up to provide the IT infrastructure and services for GST. It runs the portal for taxpayers and builds links with the tax administrations, the banking network, and systems such as the e-way bill and e-invoice. GSTN provides the technology. The power to assess, audit and enforce stays with the tax authorities, not with GSTN.

The portal has a public area, where anyone can search for a taxpayer, verify a GSTIN, and track an application. It also has a login area, where a registered person sees a dashboard with returns, ledgers, refunds, notices and profile details.

New registration is a two-stage process under Form GST REG-01. In Part A, you give the basic details: legal name as per PAN, PAN, mobile number, email and the State/UT. You verify mobile and email with separate OTPs. The portal then issues a Temporary Reference Number (TRN). In Part B, you log in using the TRN and OTP, fill in the full application, and upload documents. You then verify the application with a digital signature, e-signature or EVC, as applicable.

On successful submission of Part B after this verification, the system generates an Application Reference Number (ARN). You use the ARN to track the application. The officer then examines it. If it is in order, registration is granted and the certificate is issued in Form GST REG-06. If the officer needs more information, a notice is issued in Form GST REG-03, and you reply in Form GST REG-04.

Key rules to remember

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.

How to solve GST Portal Overview and Registration Process questions

For any question on the portal or registration, first identify whether it asks about GSTN's role, a stage of the process, or a consequence of a step. Then answer in the order the process follows.

1Read the facts and spot the stage: Part A, Part B, ARN, query or certificate.
2State what the person must have ready, such as PAN, mobile, email, proof of business and bank details.
3Apply Part A first: details entered, OTP verification on mobile and email, and the TRN issued.
4Then apply Part B: log in with the TRN, complete details, upload documents and sign or verify.
5State the outcome: ARN generated, which allows tracking of the application.
6Add the follow-up if the facts need it: query in REG-03, reply in REG-04, grant in REG-06.
7Conclude clearly: whether the application is validly filed, and what the person must do next.

Quickest way: TRN to ARN chain

When to use it: Use for MCQs and short case questions that ask which number or form comes at which stage.

Think of the chain: Part A → TRN → Part B → ARN → officer action → REG-06.
If the question mentions only basic identity and contact details such as legal name, PAN, mobile and email, the answer is Part A and TRN.
If documents and business details are uploaded and submitted, the answer is Part B and ARN.
If the question asks who runs the portal, answer GSTN. If it asks who grants registration, answer the proper officer.

Common mistakes in GST Portal Overview and Registration Process

Treating the TRN as proof of registration.
Students see that a number is issued after Part A and assume the process is complete.
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.
The portal is so visible that its operator seems to be the authority.
Fix: GSTN is an IT service provider. Registration is granted by the proper officer of the tax administration.
Mixing up what goes in Part A and Part B.
Both parts belong to the same Form GST REG-01.
Fix: Part A holds only the basic details: legal name as per PAN, PAN, mobile, email and State/UT, with OTPs for mobile and email. Everything else, including documents, goes in Part B.
Saying the ARN is issued after Part A.
Students confuse the two numbers.
Fix: TRN comes after Part A. ARN comes after a successful Part B submission.
Mixing up REG-03, REG-04 and REG-06.
The form numbers look alike and are learned without context.
Fix: Link them to action: 03 is the officer's notice, 04 is your reply, 06 is the certificate.
Leaving a TRN unused and expecting it to stay alive.
Students assume the draft is saved forever.
Fix: Complete Part B within the TRN validity period. Otherwise start again from Part A.

Worked examples

Example 1

Anil Traders, Pune, wants to register for GST. He has entered his legal name, PAN, State, mobile number and email on the portal, verified both OTPs and received a number. He thinks he can now issue tax invoices. Advise him.

Show the solution

Identify the stage: legal name, PAN, State, mobile and email with OTP verification is Part A of Form GST REG-01.
The number issued after Part A is the TRN, which is only a temporary reference.
Anil has not yet filed his application. He must log in with the TRN and OTP and complete Part B with business details, place of business, bank details and documents.
Only after Part B is submitted and verified is the ARN generated, and the officer then examines the application.
Registration is complete only when it is granted and the certificate in Form GST REG-06 is issued with a GSTIN.

Answer: Anil cannot issue tax invoices yet. He holds only a TRN. He must complete Part B to get the ARN, and he can charge tax only after registration is granted and the GSTIN is allotted.

Example 2

Choose the correct statement. (a) GSTN grants GST registration after Part B (b) ARN is generated on successful submission of Part B of Form GST REG-01 (c) TRN is generated after Part B (d) Part A requires uploading of all business documents. Explain.

Show the solution

Option (a) is wrong. GSTN is a company that provides the IT platform. The proper officer grants registration.
Option (c) is wrong. The TRN is generated after Part A.
Option (d) is wrong. Part A takes only the basic details such as legal name, PAN, State, mobile and email. Documents are uploaded in Part B.
Option (b) is right. Submission of Part B with proper verification generates the ARN, which is used to track the application.

Answer: Option (b) is correct.

Exam tips

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.

Practice questions from Walkthrough of GSTN Portal

GST Portal Overview and Registration Process in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

GST Portal Overview and Registration Process: frequently asked questions

What is GSTN and what does it do?

GSTN is a non-profit, non-government company that provides the IT infrastructure for GST. It runs the common portal and links taxpayers, tax authorities and banks. It does not decide tax liability or grant registration.

What is the difference between Part A and Part B of Form GST REG-01?

Part A collects legal name as per PAN, PAN, State/UT, mobile number and email, and ends with a TRN. Part B collects the full business details and documents, and ends with an ARN on successful submission after verification.

What is ARN in GST registration?

ARN is the Application Reference Number generated when Part B is successfully submitted. You use it to track the status of your application on the portal.

Does the TRN give me a GSTIN?

No. The TRN is only a temporary reference to let you complete Part B. The GSTIN is allotted when the officer grants registration.