GST Invoice Checklist: What to Check Before Sending to Customers

Why Invoice Approval Matters

Eligible invoices, debit notes and credit notes reported by suppliers appear in the recipient’s Invoice Management System . The recipient can accept, reject or keep eligible documents pending.

A rejected document is not included in the recipient’s GSTR-2B . However, rejection does not cancel the supplier’s invoice or IRN. The supplier must review the reason and use the appropriate correction process.

Timing creates an additional risk for businesses covered by e-invoicing. From 1 April 2025, taxpayers with aggregate annual turnover of ₹10 crore or more must report covered invoices, debit notes and credit notes to an Invoice Registration Portal within 30 days of the document date. The portal blocks IRN generation after this period.

Legal Requirements and Internal Controls

Rule 46 invoice particulars, Section 31 invoice timing and Rule 48 e-invoice requirements are statutory controls. Purchase-order matching, bank-detail verification, internal approval limits and customer-email checks are commercial controls. They are not mandatory GST invoice fields, but they help prevent payment delays and disputes.

GST Invoice Checklist Before Sending

The following table combines the important statutory and commercial checks. Rule 46 requires details such as the supplier and recipient identity, invoice number and date, HSN or SAC, description, value, tax rate, tax amount, place of supply where applicable, reverse-charge status and authentication details.

How to Review High-Risk GST Invoice Fields

Confirm the Supplier and Customer GSTINs

A GSTIN has 15 characters and is linked to a particular PAN and state registration. Correct formatting does not prove that it is the correct GSTIN for the transaction.

Confirm that the supplier GSTIN belongs to the branch making the supply. For the customer, check the registration status, state and registered business details through the GST portal’s Search Taxpayer facility.

This is particularly important where the customer has more than one GST registration. A GSTIN may be active and valid but still belong to the wrong branch or state.

Do not change the GSTIN only because the trade name looks different. First confirm the legal entity and intended registration with the customer.

Determine the Place of Supply Before Selecting the Tax Head

Place of supply is the location assigned to a transaction under the IGST Act. When read with the supplier’s location, it determines whether the supply is inter-state or intra-state and whether IGST or CGST and SGST applies.

Do not decide between IGST and CGST plus SGST only by comparing the supplier’s state with the delivery address. For goods involving movement, Section 10(1)(a) of the IGST Act generally places the supply where movement ends for delivery to the recipient.

A genuine bill-to and ship-to transaction follows a separate rule. Under Section 10(1)(b), where a third person directs the supplier to deliver the goods to another person, that third person is deemed to have received the goods. The place of supply is then the principal place of business of the person giving the direction. A different delivery state therefore does not automatically mean that the supplier must charge IGST.

For services, identify the applicable place-of-supply provision separately. Specific rules may apply to services connected with property, events, transportation and other prescribed categories.

Illustrative Example: Kirti Polymers

Kirti Polymers is registered in Maharashtra. It receives an order worth ₹4.2 lakh from a customer registered in Maharashtra, with its principal place of business in Pune. The customer directs Kirti Polymers to deliver the goods to a third party in Hubballi, Karnataka.

Assume the goods attract GST at 18%. The billing team’s first instinct may be to charge IGST of ₹75,600 because the goods are being delivered in Karnataka.

However, where Section 10(1)(b) applies, the Pune customer who directed the delivery is deemed to have received the goods. The place of supply for Kirti Polymers’ transaction is therefore Maharashtra. Kirti Polymers would charge CGST of ₹37,800 and SGST of ₹37,800 instead of IGST.

Any onward supply by the Pune customer to the person in Karnataka must be examined separately. The purchase order and delivery instruction should be retained to support the treatment.

Verify the HSN or SAC and Current Rate

Notification No. 78/2020-Central Tax prescribes the HSN digits to be mentioned on tax invoices based on aggregate turnover in the preceding financial year:

• Taxpayers with turnover above ₹5 crore must use at least six HSN digits.
• Taxpayers with turnover up to ₹5 crore must use at least four HSN digits. However, they may omit the HSN digits on invoices issued to unregistered customers.

There is no separate HSN exemption for taxpayers below ₹1.5 crore under the current notification. After confirming the classification, verify the tax rate against the latest notification and any conditions attached to the relevant entry.

The goods rate schedules were reorganised through Notification No. 9/2025-Central Tax (Rate). They were later amended by Notification No. 01/2026-Central Tax (Rate), effective from 1 May 2026, and updated through a corrigendum dated 6 May 2026. 

Where the GST rate changes between the supply date, invoice date and payment date, do not automatically apply the rate based only on the invoice date. Section 14 of the CGST Act determines the time of supply by comparing these dates, and the result decides whether the earlier or revised rate applies. This may be relevant for transactions that fall around the rate changes effective from 22 September 2025 or 1 May 2026. Before approving the invoice, check whether:

• The description matches the selected HSN or SAC.
• The rate applies to the exact goods or services.
• The notification entry contains any condition or restriction.
• An exemption or compensation cess applies.
• Any manual classification or rate override has written approval.

Also check that the HSN or SAC in the item master matches the code available in Table 12 on the GST Portal. Under the Phase 3 controls for GSTR-1 and GSTR-1A, taxpayers select the HSN from the portal dropdown instead of entering it manually. A code accepted by the billing software may therefore require correction before return filing if it does not match the portal list. 

Do not rely only on a simplified GST rate chart. Verify the exact classification and the latest applicable notification.

Check the Invoice Number, Date, and Value

Rule 46 permits one or more invoice series. Each number must be consecutive within its series, contain no more than 16 characters, and remain unique for the financial year . The invoice date must follow Section 31:

• For goods involving movement, the invoice is generally issued before or at removal.
• For goods without movement, it is generally issued before or at delivery or when the goods are made available.
• For services, the invoice is generally issued within 30 days of supply.
• Specified insurers, banks, financial institutions and non-banking financial companies generally receive a 45-day period.

Internal approval cannot extend these statutory periods. Do not backdate an invoice to include it in an earlier return period.

The checker should also recalculate the taxable value and tax. Confirm the quantity, price, eligible discount, incidental charges, tax rate, cess, tax split, rounding and final total.

A discount given before or at the time of supply can be excluded from the taxable value when it is recorded on the invoice. Post-supply discounts require separate review under Section 15 and Section 34.

Confirm E-Invoice Applicability and the Final Copy

Notification No. 10/2023-Central Tax extended e-invoicing to taxpayers whose aggregate turnover exceeded ₹5 crore in any preceding financial year from 2017-18 onwards, subject to the notified exemptions and covered document types. It took effect on 1 August 2023.

Portal enablement alone should not be treated as the final test of applicability. Check the taxpayer category, turnover history, document type, recipient category and exemptions. Where e-invoicing applies:

1. Report the document to an authorised Invoice Registration Portal.
2. Obtain a valid IRN.
3. Add the IRP-signed QR code to the final invoice.
4. Confirm that the supplier GSTIN, recipient GSTIN, invoice number, date and value in the QR data match the invoice.
5. Share the final IRN-bearing copy with the customer.

Rule 48(5) states that an invoice issued by a covered person outside the prescribed e-invoice process is not treated as an invoice.

Invoice Approval Workflow

The approval level should depend on tax risk, not only invoice value.

Set an Approval Time Limit

GST law does not prescribe a general internal approval period. Each business should set a shorter timeline based on its invoice volume, document type and tax risk.

Routine approval should normally be completed before or immediately after the document is prepared, while remaining within the Section 31 invoice deadline.

Businesses covered by the 30-day IRP reporting restriction should also maintain an exception report for documents that have been dated but have not received an IRN. Internal escalation should begin well before the 30-day limit. The approval process must support the legal deadline. It cannot extend it.

What to Do When an Error Is Found After Sharing

The correction route depends on whether an IRN was generated and whether the relevant GST returns have already been filed.

An IRN cannot be amended on the Invoice Registration Portal. It can generally be cancelled within 24 hours of generation, provided there is no active e-way bill linked to it. If an e-way bill exists, it must be cancelled before the IRN.

GSTR-1A permits specified same-period additions and amendments after filing GSTR-1 and before filing GSTR-3B. However, the recipient GSTIN cannot be changed through GSTR-1A.

A GST credit note must be declared by 30 November following the financial year in which the original supply was made, or by the date of filing the relevant annual return, whichever is earlier. The supplier cannot reduce output tax liability unless the recipient reverses the related ITC , where it was claimed. Reduction is also not allowed where the tax burden has been passed on to another person.

Records to Keep for Each Invoice

Keep the final invoice shared with the customer, purchase order or written instruction, GSTIN validation evidence, bill-to and ship-to details, place-of-supply support for unusual transactions, approval for HSN or rate overrides, IRN acknowledgement, and the names and approval times of the preparer and checker.

Also retain customer communication where an invoice was corrected, rejected, or reissued. These records explain why the invoice was prepared in a particular way and provide a clearer audit trail than tick marks alone.

Conclusion

A GST invoice checklist should confirm more than whether every field has been filled. It should establish that the selected details belong to the correct registration, transaction and tax treatment.

Before sharing an invoice, confirm the GSTINs, place of supply, HSN or SAC, current rate, invoice date and e-invoice status. Give unusual transactions and manual overrides an independent review.

A short review before sending is easier to manage than an IRN cancellation, return amendment, credit note and customer reconciliation later .