Billing Software and GST Invoicing for Small Shops: A Practical Guide

This guide is for shop owners and small traders in Bihar who still write bills by hand, or who have a billing app but are not sure their invoices are correct. You will learn how to pick billing software for a small shop, what a GST invoice must legally contain, when e-invoicing and e-way bills apply, and how to protect your data with proper backups.

Good billing is not just about looking professional. Correct invoices protect you in a GST notice, help your buyers claim input tax credit, and give you the sales numbers you need for income tax, loans and stock planning.

Why move from a hand-written bill book to billing software?

A hand-written bill book works when you make ten bills a day. It breaks down when you make a hundred. Billing software helps you:

• Calculate GST correctly on every line, including the rates that changed with the GST rate rationalisation in September 2025
• Keep invoice numbers in sequence without gaps or duplicates
• See daily sales, cash vs UPI, and outstanding dues in one screen
• Track stock and get low-stock alerts
• Send bills on WhatsApp and payment reminders
• Export data for GST returns (GSTR-1, GSTR-3B) or share it with your accountant

Types of billing and accounting software

Instead of chasing the "best" app, first decide which type suits your shop.

Mobile billing apps

These run on an Android phone, and many also work on a laptop. They are cheap or free to start, easy to learn and good for kirana, mobile accessories, cosmetics and small retail. Well-known examples in India include Vyapar and myBillBook, and there are many others. Check whether the free version limits invoices or users.

Desktop accounting software

Traditional accounting packages like Tally, Busy and Marg run on a computer and are widely used by accountants. They are strong for inventory, multiple godowns, and full books of accounts. Marg is popular with chemists and distributors because of batch and expiry tracking. They need a bit of training.

Cloud accounting software

Tools such as Zoho Books keep data online, so you and your accountant can log in from anywhere. They suit service businesses and traders who want automatic bank reconciliation.

POS systems with barcode scanners

For supermarkets, bakeries and sweet shops with fast counters, a POS setup with a barcode scanner, thermal printer and cash drawer speeds up billing. Many billing apps offer a POS mode.

How to choose billing software: a 10-point checklist

Before paying for any software, test it for a week with your real bills and check:

1. Does it create GST invoices, bills of supply and credit notes in the correct format?
2. Can it handle the GST rates and HSN codes for your products?
3. Does it work offline when the internet drops (common in many Bihar towns)?
4. Is it available in Hindi, or at least simple enough for your staff?
5. Does it support barcode printing and scanning if you need it?
6. Can you export sales data for GST returns or share with your CA?
7. Does it track stock and batch or expiry for medicines and food?
8. How many users and devices are allowed on your plan?
9. Can you back up and restore data yourself?
10. What is the total yearly cost, including renewals and add-ons?

Ask other shopkeepers in your market which app they use and how the support team responds when something goes wrong.

What must a GST invoice contain?

Under Rule 46 of the CGST Rules, a tax invoice issued by a registered person must include:

• Your name, address and GSTIN
• Invoice number: a consecutive serial number, unique for the financial year, not more than 16 characters (letters, numbers, hyphen or slash allowed), for example PAT/25-26/0457
• Invoice date
• Buyer details: name, address and GSTIN if the buyer is registered
• For unregistered buyers: where the value is ₹50,000 or more, the buyer's name, address, delivery address and state name and code; below that, only if the buyer asks
• HSN code for goods or SAC for services
• Description, quantity and unit (kg, pcs, litre)
• Taxable value, after discount
• GST rate and amount: CGST and SGST for sales within Bihar, IGST for sales to other states
• Place of supply with state name (Bihar state code is 10)
• Whether tax is payable on reverse charge
• Signature or digital signature of the supplier or authorised person

HSN digits: how many do you need?

If your aggregate turnover in the previous year was up to ₹5 crore, you must mention at least 4-digit HSN codes on B2B invoices. Above ₹5 crore, 6 digits are needed on all invoices. Good billing software lets you save the HSN code once in the product master.

Small retail bills under ₹200

If a sale to an unregistered customer is below ₹200 and the customer does not ask for an invoice, you may issue one consolidated invoice for all such sales at the end of the day. Billing software handles this automatically in most cases.

Composition dealers: bill of supply

If you are under the GST composition scheme, you cannot charge GST on your bill. Issue a bill of supply that clearly says "composition taxable person, not eligible to collect tax on supplies." Our GST registration guide for Bihar explains when composition makes sense.

E-invoicing: does it apply to you?

E-invoicing means reporting your B2B invoice to the government's Invoice Registration Portal (IRP) to get an IRN and a QR code.

• It is mandatory for businesses whose aggregate turnover exceeded ₹5 crore in any financial year from 2017-18 onwards.
• It applies to B2B invoices, credit notes and debit notes, not ordinary retail bills to consumers.
• From 1 April 2025, businesses with annual aggregate turnover of ₹10 crore or more cannot report an e-invoice older than 30 days on the IRP.

Most small shops in Bihar are below ₹5 crore and do not need e-invoicing yet. If you are growing fast, choose software that can generate e-invoices so you are ready.

E-way bill basics for Bihar traders

An e-way bill is an electronic document for moving goods, generated on the official e-way bill portal or through your software.

• For inter-state movement, it is generally required when the consignment value exceeds ₹50,000.
• For movement within Bihar, the state has notified a higher limit, widely reported as ₹1 lakh. Confirm the current limit on the e-way bill portal before relying on it.
• You need the invoice details and the vehicle number or transporter ID.
• Validity depends on distance, roughly one day per 200 km for regular cargo.

A cloth wholesaler in Bhagalpur sending ₹80,000 of sarees to Kolkata needs an e-way bill; sending the same value to a retailer in Purnia may not, if the higher Bihar limit applies.

Backups: do not lose years of billing data

Phones get stolen, laptops crash and apps shut down. Under GST, you generally have to keep accounts and records for 72 months from the due date of the annual return for that year. Protect your data:

• Turn on automatic cloud backup in your billing app and check it once a month
• Export a copy to a pen drive or external hard disk every month
• Keep your login email and mobile number updated so you can recover the account
• Give staff their own logins with limited rights, not the owner password
• Before changing software, export all invoices, parties and stock data

Also be alert to fraud aimed at shops, such as fake calls claiming your GST is blocked. Our guide on protecting your business from online fraud covers these scams.

Common invoicing mistakes to avoid

• Skipping invoice numbers or starting a new series mid-year without reason
• Charging IGST on a sale within Bihar, or CGST plus SGST on an inter-state sale
• Not updating GST rates in the item master after a rate change
• Wrong buyer GSTIN, which blocks the buyer's input tax credit
• Missing HSN codes on B2B invoices
• Mixing personal and shop UPI collections, which makes reconciliation hard

Next steps

Pick two or three billing apps, try each for a week, and choose the one your staff finds easiest. Clean billing also makes income tax simpler; see our guide to the Section 44AD presumptive scheme and our tips on managing cash flow. Then make sure customers can find you: list your business free on Bihar Directory and add the payment methods you accept to your page.

This is general information, not legal or tax advice. Confirm current GST rules on the official GST portal or with your tax consultant.