Sections 31-34 CGST — explained: this guide covers what Sections 31-34 CGST — means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Section 31 — Tax Invoice (The Most Important Document in GST)
Every registered person supplying taxable goods or services MUST issue a tax invoice. Without a valid tax invoice, your buyer CANNOT claim ITC. The invoice is the single document that creates the entire credit chain in GST.
Mandatory Contents of Tax Invoice (Rule 46)
| Field | Requirement |
|---|---|
| Supplier details | Name, address, GSTIN of supplier |
| Invoice number | Sequential, maximum 16 characters, unique per financial year |
| Date of issue | Date of invoice (determines time of supply) |
| Recipient details | Name, address, GSTIN (if registered), state code |
| HSN/SAC code | 4-digit if turnover Rs. 5 Cr+, 6-digit if Rs. 5 Cr+ |
| Description | Description of goods/services |
| Quantity and unit | For goods (not required for services) |
| Taxable value | Value before GST |
| Tax rate and amount | CGST, SGST, or IGST — rate and amount separately |
| Place of supply | State name and code (for inter-state: mandatory) |
| Signature | Digital signature or manual (physical invoice) |
Invoice Timing
For goods: before or at the time of removal (if involves movement) or delivery (no movement). Continuous supply of goods: before or at the time of each statement of account or payment.
For services: within 30 days from the date of supply (45 days for banking/insurance/financial). If invoice not issued in time: time of supply becomes the date of supply (not invoice date) — resulting in delayed payment = interest.
Section 34 — Credit Note and Debit Note
Credit Note: issued when taxable value or tax charged in the original invoice is found to EXCEED the actual value/tax. Reasons: goods returned, post-supply discount, rate difference, excess billing. Effect: reduces the supplier's output tax liability. Time limit: September 30 following the end of the FY of the original invoice, or the date of annual return, whichever is earlier.
Debit Note: issued when taxable value or tax charged is found to be LESS than actual. Reasons: price escalation, additional charges, short billing. Effect: increases supplier's output tax liability.
Recipient impact: when supplier issues credit note, recipient must REDUCE ITC by the corresponding amount. When supplier issues debit note, recipient can INCREASE ITC.
E-Invoice (Electronic Invoice) — Rule 48(4)
E-invoicing is mandatory for B2B and export invoices for businesses with aggregate turnover exceeding specified threshold:
| From Date | Turnover Threshold |
|---|---|
| October 1, 2020 | Rs. 500 crore+ |
| January 1, 2021 | Rs. 100 crore+ |
| April 1, 2021 | Rs. 50 crore+ |
| April 1, 2022 | Rs. 20 crore+ |
| October 1, 2022 | Rs. 10 crore+ |
| August 1, 2023 | Rs. 5 crore+ |
Process: Generate invoice in your accounting software → upload JSON to Invoice Registration Portal (IRP: einvoice1.gst.gov.in) → IRP validates, generates IRN (Invoice Reference Number) and QR code → invoice is valid only with IRN. Without IRN, the invoice is deemed invalid — buyer cannot claim ITC.
Auto-population: E-invoiced data auto-populates GSTR-1 (no manual entry needed for e-invoiced transactions). This reduces filing errors and reconciliation issues.
Bill of Supply — When No Tax Invoice is Needed
A Bill of Supply (not tax invoice) is issued for: (a) exempt supplies, (b) supplies by composition dealers, (c) supplies where GST is paid by recipient under RCM (some categories). Bill of supply does NOT contain tax amount — and the buyer gets NO ITC.