E-Invoicing for Small Businesses: Applicability, IRN, and QR Code Basics
Creating an invoice on a computer or sending it as a PDF does not automatically make it an e-invoice under GST.
When e-invoicing applies, the supplier must report specified invoice details to an authorised Invoice Registration Portal, commonly called an IRP. The portal validates the information and returns an Invoice Reference Number, or IRN, along with a digitally signed QR code.
Quick summary
- E-invoicing means registering specified invoice data with an Invoice Registration Portal before issuing the final invoice.
- It generally applies when PAN-level aggregate annual turnover exceeds ₹5 crore in any financial year from 2017-18 onwards.
- It covers specified B2B invoices, export invoices, and related credit and debit notes.
- B2C invoices, bills of supply, delivery challans, and quotations do not require an IRN.
- Taxpayers with aggregate annual turnover of ₹10 crore or more must report covered documents within 30 days of the document date.
- An e-invoice cannot be edited on the IRP after registration. Its IRN can generally be cancelled within 24 hours.
The supplier continues to prepare the commercial invoice using its own accounting or billing system. The IRP does not create the invoice, select the GST rate, or determine the place of supply. It only registers and authenticates the submitted data.
This guide explains who must follow e-invoicing, which documents are covered, how the registration process works, and what a business should prepare before the requirement becomes applicable.
What Is E-Invoicing Under GST?
E-invoicing is a system for electronically registering specified invoice information with an authorised IRP. The basic process is:
- The supplier prepares the invoice in its accounting or billing system.
- The prescribed invoice data is sent to an IRP.
- The IRP validates the information.
- If the information is accepted, the IRP generates an IRN and a signed QR code.
- The supplier places the signed QR code on the final invoice and issues it to the buyer.
The supplier remains responsible for the accuracy of the GSTINs, taxable value, GST rate, place of supply, and other invoice details.
E-Invoicing Applicability
E-invoicing generally applies to notified registered persons whose aggregate annual turnover exceeded ₹5 crore in any financial year from 2017-18 onwards.
The ₹5 Crore Threshold
The ₹5 crore limit became effective from 1 August 2023. This means:
- Turnover of exactly ₹5 crore does not exceed the threshold.
- Turnover above ₹5 crore may bring the registered person within the mandate.
- Any notified exemption must still be checked before deciding applicability.
How Aggregate Turnover Is Calculated
The threshold is checked on the combined turnover of all GST registrations held under the same PAN, not separately for each GSTIN. For example:
| GST Registration | Annual Turnover |
|---|---|
| Delhi | ₹2.50 crore |
| Haryana | ₹1.75 crore |
| Uttar Pradesh | ₹1.25 crore |
| Combined PAN-level turnover | ₹5.50 crore |
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Although none of the individual registrations crossed ₹5 crore, their combined turnover exceeded the limit. Subject to the notified exemptions, e-invoicing may therefore apply to the eligible GST registrations under that PAN.
Does an Earlier Year Still Count?
Yes. Once the business exceeds the threshold in an applicable financial year, a later fall in turnover does not automatically remove the requirement. For example:
| Financial Year | Aggregate Annual Turnover |
|---|---|
| 2022-23 | ₹4.20 crore |
| 2023-24 | ₹5.60 crore |
| 2024-25 | ₹4.80 crore |
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The business exceeded ₹5 crore in 2023-24. It may therefore remain covered even though its turnover fell below the threshold in 2024-25.
When Does Applicability Begin?
The turnover test considers a preceding financial year. If a business first exceeds ₹5 crore during the current financial year, that year becomes a preceding financial year only after it ends. E-invoicing would therefore generally apply from the start of the next financial year, subject to the notification in force at that time.
For example, if a business first exceeds ₹5 crore during FY 2026-27, it should generally prepare for e-invoicing from 1 April 2027.
Why IRP Status Is Not Enough
The IRP provides a facility to check whether a GSTIN has been enabled for e-invoicing. However, this status is only a support tool.
It does not replace the legal turnover test or the notified exemptions. A business should determine applicability using its PAN-level turnover and legal status. If the portal status appears incorrect, the business should raise the issue through the appropriate support channel rather than assuming that e-invoicing does not apply.
Businesses Exempt from E-Invoicing
Specified registered persons are excluded from the requirement even when their turnover exceeds the notified limit. These include:
- Insurance companies
- Banking companies
- Financial institutions, including NBFCs
- Goods Transport Agencies supplying road transport services
- Suppliers of passenger transport services
- Suppliers of admission services for cinematograph films in multiplex screens
- Special Economic Zone units
- Government departments
- Local authorities
The exemption depends on the legal category of the registered person. For example, a software company supplying services to a bank does not become exempt merely because its customer is a bank.
SEZ Units and SEZ Developers
An SEZ unit is specifically exempt from issuing e-invoices for its outward supplies. An SEZ developer does not receive the same exemption merely because it is associated with an SEZ. If the developer meets the turnover and other applicability conditions, e-invoicing may apply.
A regular supplier covered by e-invoicing must generally generate an IRN for an eligible invoice issued to an SEZ unit or developer.
Which Documents Require an IRN?
The mandate applies only to specified documents issued for covered supplies.
| Document or Transaction | IRN Generally Required? |
|---|---|
| B2B tax invoice issued to a registered buyer | Yes |
| Export invoice | Yes |
| Invoice for a supply to an SEZ unit or developer | Yes |
| Credit note relating to a covered supply | Yes |
| Debit note relating to a covered supply | Yes |
| B2C invoice issued to an unregistered customer | No |
| Bill of supply | No |
| Delivery challan | No |
| Receipt voucher | No |
| Payment voucher | No |
| Purchase order | No |
| Quotation or estimate | No |
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IRN Generally Required?
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A quotation, purchase order, or delivery challan is not reported to the IRP merely because it contains item values or GST details.
B2C Invoices and Dynamic QR Codes
Although B2C invoices do not require an IRN, certain businesses may have a separate dynamic QR code obligation. Specified registered persons whose aggregate turnover exceeded ₹500 crore in any financial year from 2017-18 onwards may be required to display a dynamic QR code on B2C invoices, subject to the applicable exemptions and conditions.
Details to Check Before IRN Generation
| Check | What to Verify |
|---|---|
| GSTIN details | Confirm the supplier GSTIN and buyer GSTIN, where applicable. |
| Document details | Check the document number, date, and type. Make sure the number has not already been used. |
| Supply details | Verify the place of supply and whether CGST and SGST, CGST and UTGST or IGST apply. |
| Item or service details | Check the description, HSN or SAC code, quantity, and unit of measurement, where relevant. |
| Tax values | Confirm the taxable value, GST rate, tax amount, and total invoice value. |
| Special transaction details | Add the required export or SEZ information, where applicable. |
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How IRN Generation Works
Step 1: Prepare the Invoice
The supplier creates the invoice using its accounting or billing system. All commercial and GST details should be checked before submission because the registered data cannot be edited on the IRP.
Step 2: Submit the Invoice Data
The prescribed invoice information is sent to an authorised IRP. Businesses using integrated software may submit the data directly through an API. Other businesses may use the portal or available offline tools to prepare and upload the required file.
Step 3: Correct Any Validation Error
If the IRP rejects the document, review the error message, correct the relevant invoice details, and submit it again. Common validation errors are explained later in this guide.
Step 4: Receive the IRN and Signed QR Code
After successful validation, the IRP generates the IRN and returns digitally signed invoice data with a signed QR code.
Step 5: Issue the Final Invoice
The billing system should place the signed QR code clearly on the final invoice before it is issued to the buyer. A covered supplier should not send an eligible tax invoice first and plan to obtain the IRN later.
IRN and Signed QR Code: What Is the Difference?
| Element | What It Is | What It Contains or Uses | Why It Matters |
|---|---|---|---|
| Invoice Reference Number | A unique reference for each registered invoice, credit note or debit note | It is created using details such as the supplier GSTIN, financial year, document type and document number | It helps prevent the same document from being registered more than once |
| Signed QR Code | A digitally signed code generated by the IRP | It generally contains the supplier and buyer GSTINs, document number and date, invoice value, number of line items, main HSN code, IRN, and IRN generation date | It allows buyers and tax officers to verify that the document was registered through an authorised IRP |
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Note: The supplier does not calculate the IRN manually. Also, the signed QR code should remain clear and scannable on both printed and PDF invoices. Many billing systems also display the IRN as readable text for easier internal reference.
Time Limit for Reporting E-Invoices
From 1 April 2025, taxpayers with aggregate annual turnover of ₹10 crore or more cannot report covered invoices, credit notes, or debit notes more than 30 days after the document date.
For example, an eligible invoice dated 1 July must be reported within the permitted 30-day period. Once the reporting window closes, the IRP will reject the document.
Businesses whose turnover exceeds ₹5 crore but is below ₹10 crore may still be covered by e-invoicing. However, the 30-day restriction does not apply to them solely because they crossed ₹5 crore. They should still register each eligible document before issuing it to the recipient.
Editing and Canceling an E-Invoice
Invoice data cannot be edited on the IRP after the IRN has been generated. If a material mistake is found, the complete IRN may generally be canceled within 24 hours of generation. Partial cancellation is not allowed.
When May Cancellation Be Needed?
The corrected document should be reviewed carefully before a fresh IRN is generated. Cancellation may be required where:
- The wrong buyer was selected
- The invoice was created twice
- The underlying transaction was cancelled
- A material invoice detail is incorrect
- The wrong tax treatment was applied
Can the Document Number Be Reused?
A document number for which an IRN has already been generated should not be reused after cancellation. The corrected invoice should use a new document number that follows the business’s invoice-numbering system.
Corrections After 24 Hours
After the 24-hour window closes, the IRN cannot normally be canceled through the IRP. The correction must then be handled through the applicable GST return and document process. Depending on the nature of the error, this may involve:
- Amending return data, where permitted
- Issuing a credit note
- Issuing a debit note
- Correcting the accounting entry
- Following another transaction-specific process
A credit note is not the correct solution for every error. For example, an incorrect buyer GSTIN or place of supply may affect the recipient’s identity or the type of tax charged. Such cases should be reviewed with a tax professional before any corrective document is issued.
How E-Invoicing Connects With GSTR-1
Registered e-invoice details are generally shared with the GST system for auto-population in the relevant sections of GSTR-1. This reduces the need for repeated data entry but does not file the return automatically. Before filing GSTR-1, the taxpayer should review whether:
- All registered e-invoices are visible
- Cancelled documents are correctly reflected
- Values match the accounting records
- Credit and debit notes are correctly classified
- B2C and other non-e-invoice transactions have been reported separately
- Export and SEZ supplies appear in the correct sections
Editing an auto-populated entry may remove or change the source, IRN, and IRN generation date displayed against it. Any change should be made only after identifying why the portal information differs from the books.
Common E-Invoicing Errors and Practical Checks
| Common Error | Practical Check |
|---|---|
| Invalid or inactive buyer GSTIN | Verify the GSTIN before preparing the invoice |
| Duplicate document number | Use controlled numbering and prevent manual reuse |
| Wrong place of supply | Check billing, delivery, and transaction details |
| Incorrect HSN or SAC code | Maintain updated item and service masters |
| Late reporting | Track unregistered documents by document date |
| Mismatched taxable value or tax | Reconcile line-item values with invoice totals |
| Missing mandatory information | Run software validation before submission |
| QR code missing from the invoice | Check the final print or PDF before issuing it |
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Failed submissions should be reviewed promptly rather than left until the return-filing stage.
Consequences of Non-Compliance
Where e-invoicing applies, an invoice issued without the required IRN and signed QR code may not be treated as a valid tax invoice under the GST rules.
Penalty and Tax Exposure
Penalties may apply for failing to issue a valid invoice, reporting incorrect particulars, or committing another GST default.
There is no single penalty amount that safely applies to every e-invoicing error. The legal consequence depends on the facts, including whether tax was paid, whether a compliant invoice was issued, and whether incorrect information was reported.
Input Tax Credit Issues
The buyer may face difficulty claiming or retaining input tax credit when the supplier was required to generate an e-invoice but failed to do so. This may lead to invoice rejection, reconciliation disputes, or delayed payment.
Return and IRP Mismatches
Invoices appearing in the books or GSTR-1 without corresponding IRP registration may be identified during reconciliation or scrutiny.
E-Invoicing Readiness Checklist
Prepare for e-invoicing in three stages:
| Stage | What to Do |
|---|---|
| 1. Confirm Applicability | Check the PAN-level turnover, identify the date from which e-invoicing applies, and verify whether any notified exemption is available. |
| 2. Set Up the Process | Separate covered documents from non-covered documents, connect the billing system to an authorised IRP, and set document-number controls to prevent duplication. The setup should be completed before the first applicable invoice is issued. |
| 3. Assign and Monitor | Decide who will handle IRN generation, failed submissions and cancellations. Configure the 30-day reporting alert where applicable and reconcile IRP data with GSTR-1 before filing. |
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Keeping billing records organised can make the transition easier. mazu helps small businesses manage invoices and day-to-day business records in one place as their operations grow.
Conclusion
E-invoicing is the registration of specified invoice data with an authorised IRP. It is not simply the creation of an invoice on a computer.
The requirement generally applies when PAN-level aggregate annual turnover exceeded ₹5 crore in any financial year from 2017-18 onwards. Covered businesses must register specified B2B invoices, export invoices, and related credit and debit notes before issuing them.
A clear invoicing process, accurate data, and timely registration can reduce IRP errors, buyer disputes, and return mismatches.