GST in Daily Business Operations

Learning Objectives

• Know every mandatory field on a GST tax invoice
• Understand when to issue a Bill of Supply instead of a Tax Invoice
• Create Credit Notes and Debit Notes correctly
• Understand e-Invoice applicability and process
• Know when an e-Way Bill is required and how to generate one
• Apply all five conditions for valid ITC claim

The Tax Invoice — Your Most Important GST Document

A Tax Invoice is the fundamental document in GST. Without a valid tax invoice, the buyer cannot claim Input Tax Credit. Getting it right is not optional — errors can cost your buyer their ITC.

Mandatory Fields on Every Tax Invoice

Invoice series rules:

• Each financial year starts fresh: SR-2025-0001 for FY 2025-26
• Multi-digit prefix allowed: SR/HYD/2025-26/0042
• No gaps allowed in the sequence
• If an invoice is cancelled, that number cannot be reused

Time Limit for Issuing Invoice

Invoice Issue-Deadline Matrix — Quick Reference

Different supply scenarios trigger different deadlines. Get the deadline wrong and the invoice itself can be challenged in audit — interest applies on tax not deposited within the period the invoice should have covered.

Why 45 days for banks/NBFCs? Their billing cycles are monthly statement-based, and many service charges are computed at month-end. The law accommodates this with the extended window — but they can't use it for one-off transactions, only for cycle-end billings.

Why two voucher types for advances? Goods supply: GST is on actual supply, so the advance gets a Receipt Voucher (no tax invoice yet). Services: GST is on the advance itself, so a Tax Invoice must be raised within 30 days even though the service hasn't been performed.

Bill of Supply

A Bill of Supply is issued instead of a Tax Invoice in two cases:

1. Exempt goods or services — no GST to show (e.g., fresh vegetables, healthcare)
2. Composition Scheme dealers — not permitted to charge GST

Looks similar to a Tax Invoice but carries the words "Bill of Supply" and does not show any GST amount.

Sunrise Retail deals only in taxable goods → they always issue Tax Invoices, never Bills of Supply.

Credit Notes and Debit Notes

Credit Note — When Issued by Supplier

A credit note reduces the tax liability of the supplier and the ITC of the buyer.

Situations:

• Sales return (buyer returns goods)
• Price reduction after supply (post-supply discount)
• Goods found deficient in quantity or quality

Time limit: Earlier of — (a) 30th November following the end of the financial year, or (b) date of filing annual return.

Debit Note — When Issued by Supplier

A debit note increases the tax liability.

Situations:

• Undercharged tax in original invoice
• Additional charges after supply

Time limit: No specific limit — any time.

Fields: Same as Tax Invoice, plus original invoice number and date, and reason for the note.

Debit Note vs Credit Note — Accounting Entries

The journal entries differ depending on whether you're the supplier (issuing the note) or the recipient (receiving it). Both sides must mirror each other in their books and in their GSTR-1 / GSTR-3B filings — any mismatch shows up in GSTR-2B reconciliation.

Credit Note for Sales Return (₹32,000 worth of phones returned by Digital Hub)

In the SUPPLIER's books (Sunrise Retail):

Logic: Reduce sales (Sales Returns is a contra-account to Sales). Reduce the CGST/SGST already charged to the buyer (debit Output CGST/SGST to reverse it). Reduce the receivable from Digital Hub by the full invoice-value reduction.

In the RECIPIENT's books (Digital Hub):

Logic: Reduce the payable to Sunrise Retail by ₹37,760. Reduce the original purchase (Purchase Returns offsets Purchases). Reverse the Input CGST/SGST that was earlier claimed as ITC — this is the ITC reversal entry that ultimately flows into GSTR-3B Section 4(B).

Both sides must report this credit note in their respective GST returns:

• Sunrise Retail: GSTR-1 Table 11 (CDN for registered buyers) → reduces output tax in GSTR-3B Section 3.1(a)
• Digital Hub: appears in their GSTR-2B → must reduce ITC in GSTR-3B Section 4(B) (ITC reversed)

If only one side reports it, the other becomes a mismatch flag at year-end reconciliation.

Debit Note for Under-Billing (₹15,000 omitted on original invoice)

Say Sunrise Retail's original invoice missed a freight charge of ₹15,000 that should have been billed. A debit note adds it back.

In the SUPPLIER's books (Sunrise Retail):

Logic: Increase the receivable from Digital Hub (they now owe ₹17,700 more). Recognise the additional income. Increase the output CGST/SGST liability — these flow into GSTR-3B Section 3.1(a) as additional output tax for the period.

In the RECIPIENT's books (Digital Hub):

Logic: Recognise the additional expense / purchase cost. Claim additional ITC (assuming all five ITC conditions are met). Increase the payable to Sunrise Retail.

Memory hook: Credit note flows backwards through the original entry (sales reduces, GST reduces, debtor reduces). Debit note flows forwards through the original entry (sales increases, GST increases, debtor increases). The signs flip on the recipient's side because each entry is a mirror.

E-Invoice — Electronic Invoice

E-Invoice is NOT a separate invoice — it is your regular tax invoice, reported to the GST portal in real time, which stamps it with a unique IRN (Invoice Reference Number) and QR Code.

Who Must Issue E-Invoice?

Sunrise Retail's projected turnover: ₹1.2 Crore → Below ₹5 Crore → E-Invoice NOT mandatory.

However, they should understand the process for future growth.

E-Invoice Process

Prepare invoice in Tally/ERP
        ↓
Upload JSON to IRP (Invoice Registration Portal): einvoice1.gst.gov.in
        ↓
IRP validates, generates IRN (64-character hash)
        ↓
IRP signs invoice digitally + adds QR Code
        ↓
Signed e-invoice returned — print and share with buyer
        ↓
Data auto-flows to GSTR-1 (no manual entry needed!)

IRN = SHA-256 hash of (Supplier GSTIN + Financial Year + Invoice Series + Invoice Number). It is unique and cannot be regenerated if the invoice is cancelled.

E-Way Bill — Movement of Goods

An E-Way Bill is an electronic document required for movement of goods worth more than ₹50,000 (invoice value).

When Is E-Way Bill Required?

When Is E-Way Bill NOT Required?

• Goods transported by non-motorised vehicle
• Goods transported by customs under customs bond
• Empty cargo containers
• Goods under customs seal
• Petroleum products, alcoholic liquor (outside GST)
• Specified goods (e.g., vegetables, fruits, milk)

E-Way Bill Components

Part A — filled by supplier or buyer:

• Invoice/document number and date
• GSTIN of supplier and recipient
• Place of delivery (PIN code)
• Value of consignment
• HSN code
• Reason for transport

Part B — filled by transporter:

• Vehicle number / transport document number (for railways, air, ship)

Validity:

Input Tax Credit (ITC) — The Five Conditions

ITC is the credit for GST paid on purchases. To claim it, all five conditions under Section 16 must be met:

ITC — What Is NOT Allowed (Section 17(5))

Certain goods and services are blocked — no ITC even with a valid invoice:

Sunrise Retail — Case Study Application

💼 Sunrise Retail Pvt Ltd

Complete Tax Invoice — SR-2025-0042

╔══════════════════════════════════════════════════════════════════╗
║                        TAX INVOICE                               ║
╠══════════════════════════════════════════════════════════════════╣
║ SUNRISE RETAIL PVT LTD                                           ║
║ Plot 45, 2nd Floor, Madhapur Main Road                           ║
║ Hyderabad, Telangana — 500081                                     ║
║ GSTIN: 36AACCS1234A1ZP | PAN: AACCS1234A                        ║
║ Phone: 040-XXXXXXXX | Email: billing@sunriseretail.in            ║
╠══════════════════════════════════════════════════════════════════╣
║ Invoice No: SR-2025-0042          Date: 10-Apr-2025              ║
║ Place of Supply: Telangana (36)                                   ║
╠══════════════════════════════════════════════════════════════════╣
║ BILL TO:                                                          ║
║ Digital Hub Retail Pvt Ltd                                        ║
║ Shop 12, Secunderabad Market, Hyderabad                           ║
║ GSTIN: 36AAADH4321E1ZQ                                           ║
╠══════════════════════════════════════════════════════════════════╣
║  Item           HSN   Qty   Unit Rate    Amount   CGST   SGST    ║
║                                                   9%     9%      ║
║  Samsung X      8517   30   Nos  16,000  4,80,000 43,200 43,200  ║
╠══════════════════════════════════════════════════════════════════╣
║  Taxable Value:  ₹4,80,000                                        ║
║  CGST @ 9%:      ₹43,200                                          ║
║  SGST @ 9%:      ₹43,200                                          ║
║  Total Tax:      ₹86,400                                           ║
║  Total Invoice:  ₹5,66,400                                        ║
║  Amount in words: Five Lakhs Sixty-Six Thousand Four Hundred Only ║
╠══════════════════════════════════════════════════════════════════╣
║  ITC Eligibility: Full ITC eligible to recipient                  ║
║  Whether goods are pre-packaged and labelled: Yes                 ║
╠══════════════════════════════════════════════════════════════════╣
║  Authorised Signatory: Kiran Sharma (MD)              (Signature)║
╚══════════════════════════════════════════════════════════════════╝

Tax Invoice — SR-2025-0048 (Interstate to CloudStore Bangalore)

Key differences from the Secunderabad invoice:

Taxable value for CloudStore = 20 phones × ₹16,500 = ₹3,30,000. IGST = ₹3,30,000 × 18% = ₹59,400.

Credit Note — CN-2025-0005 (Apr 24 Return from Digital Hub)

CREDIT NOTE — CN-2025-0005
Date: 24-Apr-2025
Against Invoice: SR-2025-0042 (10-Apr-2025)
Reason: Sales return — 2 phones, quality issue

Samsung X (HSN 8517): 2 Nos × ₹16,000 = ₹32,000
CGST @ 9%: ₹2,880
SGST @ 9%: ₹2,880
Total Credit: ₹37,760

Impact: Sunrise Retail's CGST liability reduced by ₹2,880. Digital Hub's ITC reversed by same.

E-Way Bill Check for April Transactions

ITC Eligibility Check for Sunrise Retail (April 2025)

ITC: The Five Conditions — Visual Checklist

Before claiming any rupee of ITC, Sunrise Retail must tick all five boxes. Miss one and the ITC is invalid — even if the invoice is genuine.

┌────────────────────────────────────────────────────────────────────┐
│       ITC ELIGIBILITY CHECKLIST — ALL 5 REQUIRED                    │
├────────────────────────────────────────────────────────────────────┤
│                                                                      │
│  ☑  1. REGISTERED                                                   │
│       Sunrise Retail GSTIN: 36AACCS1234A1ZP — Active ✓              │
│                                                                      │
│  ☑  2. VALID TAX INVOICE                                            │
│       TechWorld invoice dated Apr 5: IGST ₹2,16,000                │
│       → Contains all 14 mandatory fields ✓                          │
│                                                                      │
│  ☑  3. GOODS RECEIVED                                               │
│       100 phones physically received Apr 5 — delivery note signed ✓ │
│                                                                      │
│  ☑  4. SUPPLIER PAID TAX (appears in GSTR-2B)                      │
│       TechWorld (27AACCT8901F1ZN) files GSTR-1 on time             │
│       → Sunrise Retail sees SR-2025-0042 in GSTR-2B May 14 ✓       │
│                                                                      │
│  ☑  5. RETURNS FILED                                                │
│       Sunrise Retail files GSTR-3B by May 20 ✓                     │
│                                                                      │
│  RESULT: ₹2,16,000 IGST ITC is VALID — can be used in May GSTR-3B │
└────────────────────────────────────────────────────────────────────┘

What if TechWorld had NOT filed GSTR-1?
  → Condition 4 fails
  → ITC NOT visible in GSTR-2B
  → Sunrise Retail cannot claim ₹2,16,000
  → Tax payable in cash instead
  → Real cost: ₹2,16,000 locked until TechWorld files

Sunrise Retail's ITC Eligibility — April 2025 Purchases

Total eligible ITC for April: IGST ₹2,16,000 + CGST ₹2,700 + SGST ₹2,700 = ₹2,21,400

Worked Example — Credit Note Accounting

Sunrise Retail issued credit note CN-2025-0005 for 2 returned phones.

Before credit note:

Sales: ₹4,80,000 (30 phones)
CGST output: ₹43,200
SGST output: ₹43,200

After credit note:

Net Sales: ₹4,80,000 − ₹32,000 = ₹4,48,000
Net CGST output: ₹43,200 − ₹2,880 = ₹40,320
Net SGST output: ₹43,200 − ₹2,880 = ₹40,320

This is exactly what goes into GSTR-3B — the net figures after credit notes.

Practice Exercise

Exercise 1: Sunrise Retail sells 5 laptops (HSN 8471) at ₹55,000 each to a buyer in Chennai (Tamil Nadu, state code 33). The buyer's GSTIN is 33AABCD1234E1ZF. Prepare the key fields of the tax invoice.

Exercise 2: Kiran gets an invoice from a travel agent for company trip — ₹50,000 + GST ₹9,000 (cab service). Can Sunrise Retail claim this ITC?

Key Terms

Checklist — what you should now be able to do:

• Prepare a complete GST tax invoice with all 14+ mandatory fields
• Know when to issue a Bill of Supply vs a Tax Invoice
• Create a credit note and link it to the original invoice correctly
• Determine whether a transaction requires an e-way bill and calculate its validity
• Apply all five ITC eligibility conditions and identify any blocked items under Section 17(5)