Invoice with Bank Details is a specific document with specific rules, not a style of invoice. This page covers the content it requires, the numbering, the timing, and the documents it sits next to.
The document family, in one place
Almost every mistake in this area comes from treating these as different names for an invoice. They are not; they do different things and some of them must not carry tax at all.
A tax invoice is issued on a taxable supply by a registered supplier and shows the tax separately, so the buyer can claim input credit. A bill of supply is issued where no tax is charged — exempt supplies, or a composition dealer — and must not show a tax amount. A proforma invoice is a quotation laid out like an invoice: not a tax document, no credit claimable, and it must stay out of your invoice series. A credit or debit note corrects an invoice already issued, referencing it. A receipt voucher covers an advance taken before a supply, and a refund voucher covers giving that advance back. A delivery challan moves goods where there is no supply.
If you can place the document you are about to issue in that list, you have avoided most of what goes wrong.
Bank details on an invoice: not mandatory, and worth it anyway
Bank details are not in the prescribed content for a tax invoice. They are on almost every invoice that gets paid promptly, which tells you something about what an invoice is actually for.
What a payer needs is the account name exactly as the bank holds it, the account number, and the IFSC. A missing or wrong IFSC is the single most common cause of a payment sitting in someone's approval queue for an extra week. A UPI ID or QR code alongside helps a small customer pay in seconds; some businesses print both.
Two cautions. Put them in one place on the document, consistently — bank details that move around the page between invoices are the thing a fraudulent copy exploits. And if your details ever change, tell customers through a channel other than the invoice itself, because "our bank details have changed" on an emailed PDF is the oldest invoice fraud there is.
The other field that affects payment more than people expect is the due date. "Payment terms: 15 days from invoice date — due 20 May" is harder to ignore than "immediate".
Issuing these properly, free
- Tax invoices with the complete prescribed field set, tax split per line.
- Bills of supply for exempt and composition supplies, with no tax line.
- Proformas and quotations in their own series, converting to an invoice without retyping.
- Credit and debit notes that reference the original invoice rather than editing it.
- Separate consecutive series per document type, issued centrally so a number cannot repeat.
- Tax derived from the place of supply, so CGST/SGST against IGST is never a judgement call.
- A receivables position — what is unpaid, how old, and whose.
- Export of everything to CSV, Excel and JSON, on every plan.
- ₹0 on the free plan, no card, no expiry.
Issuing the right document, in order
- Decide what the transaction is: a taxable supply, an exempt supply, an offer, a correction, or money received in advance.
- Pick the document that matches it — a tax invoice, a bill of supply, a proforma, a credit or debit note, or a receipt voucher.
- Check your registration position. If you are not registered, or are under composition, a tax invoice showing tax is the wrong document.
- Use the series belonging to that document type, and let the number be issued rather than typed.
- Fill the mandatory content — including place of supply and HSN or SAC per line, which are the two most commonly omitted.
- Issue it within the time limit that applies to your type of supply.
- Keep it, and the records behind it, for the prescribed retention period.
Timing: when the document has to exist
Issuing the right document late is its own problem, separate from issuing the wrong one. The time of supply decides when tax becomes payable, and the invoice date is one of the inputs to it — so an invoice raised whenever it is convenient can move a liability into a period you have already filed.
The limits differ by what is being supplied. For goods the trigger is tied to removal or delivery; for services it is tied to completion of the supply, within a prescribed number of days. Continuous supplies, supplies on approval and reverse-charge supplies each have their own rule.
The practical version of this is unglamorous: raise the invoice when the supply happens, not when the customer asks for it, and not in a batch at month end because that is when someone has time.
These limits have been amended before. Check the one applying to your type of supply rather than relying on a remembered number of days.
Keeping the documents for as long as you have to
Invoices and the records behind them must be retained for a prescribed period counted from the due date of the annual return for that year, not from the date on the document — so the obligation runs considerably longer than most people assume. Check the period currently in force for your own case.
That has a practical consequence. A laptop, a phone and a folder of PDFs are not a retention plan, because the horizon outlasts most hardware and most staff. Where records are kept electronically they have to stay accessible and readable for the whole period, which means a format you can still open and a copy somewhere other than the machine that produced it.
It is also worth keeping them in a form that can be searched and totalled, not only read. When records are actually asked for, the request is rarely "send me invoice 412" — it is a period, a customer or a figure that has to be reconciled.
Dull, cheap to do, and expensive to reconstruct. Those three things together are why it is worth doing now rather than later.
HSN and SAC codes, and how many digits you need
Every line on a tax invoice needs an HSN code for goods or a SAC for services. How many digits depends on your aggregate turnover in the preceding financial year — smaller businesses report fewer digits than larger ones, and B2B and B2C invoices are treated differently.
Because the requirement is tied to turnover and has been tightened in stages, the practical answer is to store the fullest code you can against each product once, and let the software report at the level required. A six-digit code can always be truncated; a two-digit one cannot be expanded.
Billixo keeps the code on the product record and carries it onto every line automatically, and its AI HSN lookup will suggest one from a plain description when you genuinely do not know.
Invoice numbering: one unbroken series per year
The invoice number has to be consecutive, unique within the financial year, and no more than sixteen characters of letters, numbers, slashes and hyphens. Gaps invite questions. Duplicates cause them.
This is the single most common reason a spreadsheet-based billing setup fails an audit: two people billing on two machines, both starting from the last number they remember. A system that issues the number centrally cannot make that mistake.
The series restarts on 1 April, and Billixo restarts it for you rather than waiting to be told.
The AI, and what it is actually for
The useful application of AI to billing is not a chatbot. It is the twenty minutes a day spent retyping things that already exist on paper.
- Scan a supplier bill. Photograph it; the lines, the GSTIN, the tax and the totals come back as a draft you check rather than a form you fill.
- Find the HSN code. Describe the product in plain words and get a code to confirm, instead of scrolling a list of eleven thousand.
- Ask about your own numbers. "What is outstanding over sixty days?" answered from your data, not a manual.
- Write the reminder. A polite, specific chase for an overdue invoice, ready to send on WhatsApp.
Nothing is sent anywhere until you ask for it, and the platform runs on whichever model it has been configured with — including one hosted on your own server.
Who this actually suits
It fits a business that raises between a handful and a few hundred invoices a month and would rather not think about GST between the 10th and the 20th: traders, distributors, retail counters, workshops, agencies, consultants, contractors and manufacturers who sell on invoice.
It fits less well if you need deep manufacturing costing, multi-currency consolidation, or payroll — those are different products, and pretending otherwise wastes your evaluation time.
If you are not sure which side of that line you fall on, the free plan answers it in an afternoon at no cost. Start free now.
Free, and what it costs you instead
Free software usually costs you something that is not money: your data held hostage, an export that does not work, ads inside your invoice, or a "free" tier so narrow it is a demo with a login screen.
The line here is drawn differently. Export works on the free plan — CSV, Excel and JSON — because data you cannot get out is not data you own. The invoice is a real compliant invoice, not a sample. The limits are on volume and on the conveniences, not on whether the thing works.
Start free now. If it does not suit you, take your data with you.
Where your data lives
On the server this platform is installed on. Every record carries a company identifier and every query is scoped to the signed-in account at the framework level, so one business cannot read another’s data by any route, including a crafted one.
Sign-in is rate limited, sessions can be restricted to one device per user, and passwords are stored hashed. Exports are available on every plan, free included: if you ever want to leave, your data leaves with you.
Frequently asked questions
Can I edit an invoice after issuing it?
No. Once it has gone to the customer you issue a credit note or a debit note referencing the original. Editing the original leaves two versions of one invoice number in two sets of books, and the mismatch surfaces at reconciliation — usually in the following month.
Do I need a separate number series for each document type?
Yes, in practice. Each series has to be consecutive and complete within the financial year, so a proforma or a credit note that consumes a tax invoice number leaves a gap you then have to explain. Give each document type its own prefix.
What happens if I cancel an invoice?
The number stays with it and the invoice remains in the series marked as cancelled. It is not handed back for reuse — reusing it leaves a gap in your records and a figure in your customer's.
What happens to my data if I stop paying?
Nothing is deleted. The account settles back onto the Free plan: the paid conveniences switch off, the volume limits return, and every invoice, customer and product you created stays exactly where it is — including the export.
Does it work on a phone?
Yes. It is a browser application that adapts to the screen, so the same account works from a desktop at the counter and a phone in the market. There is no separate app to keep in step.
Start free, decide later
You do not have to choose a plan to begin. Start on Free, use it for as long as it suits you, and upgrade only when a limit actually gets in your way — never automatically, and never because a countdown ran out.
Open the software demo → — or create the free account from the same page.
Read the full details → on the home page, including pricing and the AI features.
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