2) Thresholds & schemes (big picture)

A. Thresholds for mandatory registration (typical positions used in practice)

• Suppliers of goods (in most States): up to ₹40 lakh aggregate turnover (opt-in, subject to State adoption and exclusions).
• Suppliers of services (and mixed suppliers): up to ₹20 lakh (₹10 lakh for “special category” States).
• Special category States (NE/Hilly States) often follow lower thresholds (commonly ₹10–20 lakh).
• Aggregate Turnover = PAN-wise turnover across India (taxable + exempt + exports + inter-state), excluding GST/cess.

B. Composition Scheme (Sec. 10 CGST)

Who: Small taxpayers within limits, primarily B2C, not engaged in inter-State outward supply (with limited exceptions by notification), not supplying through most e-commerce operators (ECO) where TCS applies, and not making non-taxable supplies of certain goods.

Common limits & rates (indicative):

• Manufacturers/traders up to ₹1.5 crore → around 1% (0.5%+0.5%).
• Restaurants (non-alcohol) → around 5% (no ITC).
• Service providers / mixed suppliers under special compo-like scheme → up to ₹50 lakh at 6% (3%+3%) (notification-based).

Impact: No ITC; issue Bill of Supply (not tax invoice); pay tax from own pocket; place “Composition taxable person” declaration at premises and on invoices.

3) Compulsory registration (even if below threshold) — Sec. 24 CGST

• Inter-State taxable supply (subject to relaxations/notifications—especially for services).
• Casual taxable persons (CTP) and Non-resident taxable persons (NRTP).
• Persons required to pay tax under reverse charge (RCM) in specified cases.
• E-commerce operators (ECO) liable to collect TCS or to pay tax under Sec. 9(5) for notified services.
• Input Service Distributor (ISD).
• Persons making taxable supplies on behalf of others (agents).
• TDS deductors under Sec. 51 and TCS collectors under Sec. 52.

🧭 E-commerce nuance: Registration rules for small service providers selling via ECO have been relaxed in specific cases (esp. where ECO pays tax u/s 9(5)). Goods sellers through ECO generally need registration. Always check the current notification for your model.

4) Types of registration

• Regular (normal taxpayer).
• Composition (CMP-02 intimation).
• CTP/NRTP (advance deposit of estimated tax; time-bound registration).
• ISD (to distribute input credit of services within a PAN).
• TDS/TCS registrations (Govt entities/ECO).
• OIDAR (online information/database access/retrieval services from outside India).

5) Documents checklist (entity-wise)

For Proprietor

• PAN (proprietor), Aadhaar, photo, email & mobile (OTP).
• Proof of principal place (rent agreement/consent letter + utility bill).
• Bank proof (cancelled cheque or bank passbook page).

For Partnership/LLP/Company

• PAN of entity; Constitution docs (Partnership Deed/LLP Agreement/COI + MOA/AOA).
• PAN, Aadhaar, photos of promoters/partners/directors and authorized signatory (Board Resolution/Authorization).
• Registered/principal place proofs as above.
• Bank proof.
• Additional: For multi-State registrations, separate application per State (GST is State-wise).

🔐 Aadhaar authentication is significant—if not completed or flagged, physical verification of premises or additional documents may be required.

6) Registration process — portal flow (gst.gov.in)

• New Registration → choose taxpayer category; enter PAN, State, email, mobile → get TRN (temporary reference).
• Part-B: Fill legal name, trade name, constitution, date of starting, HSN/SAC major, bank details, principal and additional places, authorized signatory.
• Upload documents (size/format limits apply).
• Aadhaar e-KYC for signatory and promoters (VCIP/OTP).
• E-verification: EVC/DSC (DSC mandatory for companies).
• ARN generated → application goes to jurisdictional officer.
• Approval (usually within 7 working days; can be deemed approved if timelines lapse).
• GSTIN & Registration Certificate (REG-06) issued; start compliance from effective date.

⏳ Timelines & risk: In case of query (REG-03), reply (REG-04) within due date. Non-response → rejection (REG-05).

7) Post-registration essentials (what changes the next day)

• Invoices: Start issuing Tax Invoices with GSTIN, invoice number (unique, consecutive), date, legal name, address, HSN/SAC, taxable value, tax rate/amount, place of supply, etc. Composition issues Bill of Supply.
• ITC: Eligible from effective date; credit on pre-registration stock (including inputs in semi/finished goods) may be claimed within 30 days via declaration (Rule 40).
• Returns & payments (popular defaults):
  • GSTR-1 (outward supply), GSTR-3B (summary payment).
  • Quarterly option under QRMP for eligible small taxpayers (with monthly challan via PMT-06).
  • Annual return GSTR-9, and GSTR-9C (reconciliation statement) depending on turnover thresholds.
  • Composition: quarterly CMP-08 + annual GSTR-4.
• E-way Bill: Required for movement of goods above prescribed value (commonly ₹50,000) with specific exceptions.
• E-invoicing: Mandatory if your aggregate annual turnover crosses the notified limit (progressively reduced; many taxpayers ≥ ₹5 crore are already covered). Check your AATO status.
• Display: GSTIN must be displayed at place(s) of business; registration certificate to be exhibited.
• Banking & ERP: Map GSTINs, HSN/SAC, place-of-supply logic, and reverse charge flags; align with accounting, e-invoicing IRP, and e-way systems.

8) Place of Supply (why clients get it wrong)

Determines IGST vs CGST+SGST and registration footprint.

• Goods: Generally location where movement terminates for delivery; special rules for bill-to/ship-to, installation, on-board supplies, import/export.
• Services: Generally location of recipient; exceptions for immovable property, events, performance-based services, transportation, OIDAR, intermediaries, etc.
• Exports/SEZ: Zero-rated supplies under IGST Act; documentation + LUT/refund mechanics apply.

❗ Insight: Many errors arise from treating “shipping from State A” as intra-State when recipient/place of supply is State B (→ IGST). Wrong PoS = wrong tax head = cash flow + penalty exposure.

9) Reverse Charge Mechanism (RCM)

• Section 9(3) (CGST) & 5(3) (IGST): RCM on notified goods/services (e.g., GTA in many cases, legal services by advocates to business recipient, sponsorship, etc.).
• Section 9(4): RCM on supplies from unregistered to notified classes of registered persons (not a blanket rule any more).
• Effect: Recipient pays GST in cash; can take ITC (subject to eligibility). Ensure RCM ledger and timely 3B reporting.

10) Amendments, cancellation & revocation

• Amendment (core/non-core) via REG-14 on portal; certain changes (legal name, address, promoter details) may trigger officer approval.
• Suo-motu cancellation or by officer for non-filing etc. (Sec. 29).
• Revocation within the prescribed period via REG-21 after filing pending returns & paying dues.
• Multiple places: Add additional places where goods are stored or services delivered to avoid e-way or inspection issues.

11) Penalties, interest & late fees (commercial reality)

• Non-registration when liable: penalty under Sec. 122 (higher of ₹10,000 or tax evaded), detention/seizure risks on movement without proper documents.
• Interest: Typically 18% p.a. on delayed payment of tax.
• Late fees: Per-day late fees for GSTR-1/3B (capped/relaxed via notifications for small taxpayers); composition and annual returns have separate slabs.

12) Practical insights & common pitfalls

• PAN-wise view: Threshold is PAN-aggregate; opening a new branch in another State does not reset limits.
• Deemed distinct persons: Each State registration under same PAN is a distinct person → cross-charge or ISD is needed for inter-branch services/credits.
• HSN/SAC accuracy: Impacts rate, e-invoicing schema, and GSTR-1 tables; disclose the minimum HSN digits mandated for your turnover slab.
• Vendor compliance: Your ITC is contingent on supplier’s correct reporting (linked to GSTR-2B). Build vendor scorecards and contract clauses.
• E-commerce & 9(5): If ECO pays tax for your service category, you may not charge GST; understand your exact route (commission vs marketplace).
• Exports/LUT: Keep LUT in place for zero-rated supplies without payment of tax; preserve FIRC/BRC and shipping documents.
• CTP/NRTP: Plan cashflows—advance tax deposit required; renew before expiry for fairs/exhibitions.
• Pre-registration ITC: Take it within time using the correct form; maintain stock statements and invoices in your name.
• E-way/E-invoice integration: Align ERP so IRN/e-way data matches invoice; mismatches lead to detention or denial of ITC.
• Books & reconciliations: Monthly GSTR-1 vs 3B vs 2B and annual 9/9C reconciliations prevent interest/penalty surprises.

13) Quick client checklist (registration)

• PAN, Aadhaar (auth done), email & phone active.
• Constitution documents & authorization (BR/LOA).
• Premises proof (rent/consent + utility bill) and signage.
• Bank proof; major HSN/SAC mapped.
• Decide scheme (regular vs composition) and effective date.
• Aadhaar e-KYC completed to avoid physical verification.
• Post-approval: invoice series created; e-invoicing & e-way bill set up; accounting heads mapped.