A format is a starting point, not a system. Bill Format PDF is worth getting right, so this page sets out exactly what has to appear on the document, what is optional, and what quietly makes it invalid.
A format is a layout. An invoice is a record.
A template gets the first bill out of the door, and for a business issuing two or three a month that is a perfectly reasonable answer. Nobody needs software to send three invoices.
What a file cannot do is remember. It will not stop you reusing a number, it will not notice that a customer was billed twice, and it will not tell you in April what was still unpaid in February. Every one of those is a matter of record-keeping rather than of layout.
So the useful way to read this page is: get the content right first, because that is a legal question, and only then decide whether a file or a system should hold it.
The eight lines people leave off
- A number that cannot repeat. One series, consecutive, unique within the financial year. Two people with two copies of a file is how this breaks.
- Your GSTIN, spelled exactly as registered.
- The customer's GSTIN where they are registered — without it they cannot claim the credit, and they will ask again.
- Place of supply on anything inter-state. This decides the tax, so guessing it wrong is not a cosmetic error.
- HSN or SAC on every line, not just on the first one.
- The taxable value per line, before tax, shown separately from the tax.
- Each tax head on its own line — CGST and SGST, or IGST. Never one combined "GST" figure.
- Reverse charge marked where it applies, even when the answer is no.
PDF is the right thing to send, and the wrong thing to keep
PDF is the correct delivery format. It looks the same everywhere, it cannot be casually altered, it prints predictably and it attaches to anything. Every invoice you send should go as a PDF rather than as an editable file.
What it is not is a record. A folder of PDFs cannot be totalled, searched by amount, aged into a receivables list or exported into a return. Each one is a picture of a transaction, and the transaction itself is nowhere.
So the pattern that works is: keep the data, generate the PDF. The document is produced from the record on demand, which also means a correction regenerates the document rather than leaving two versions of it. Working the other way round — making the PDF first and hoping the folder is the record — is what makes year end take a fortnight.
If a customer asks for an editable invoice, they are usually asking for something they should not have. Send the PDF and issue a credit note if something was genuinely wrong.
What you get here instead of a file
- Every mandatory field present, because the document is built from records rather than typed into a layout.
- One numbering series, issued centrally, consecutive, restarting each financial year — so a number cannot be used twice.
- Customers stored once with GSTIN, address and state, so the details are right on the fortieth invoice too.
- Items stored once with HSN or SAC, rate and tax.
- The tax derived, not chosen — CGST and SGST or IGST, from the place of supply against your registration state.
- A clean PDF to print, email or send on WhatsApp.
- An answer to "what is unpaid", which no template has ever been able to give.
- Your data exportable to CSV, Excel and JSON at any time, on every plan including the free one.
- Free — ₹0, no card, no expiry.
From a template to a proper invoice in about five minutes
- Start free now — an email address and a password, no card.
- Enter your business name, address and GSTIN once. These are the fields you have been retyping.
- Add a customer with their GSTIN and state, or import your whole list from the spreadsheet you already have.
- Add the items you sell with their HSN or SAC codes and rates.
- Set the invoice number your series should carry on from, so there is no gap and no restart.
- Raise the invoice. The number, the tax split and the totals are already filled in.
- Download the PDF, or send it straight to the customer.
The numbering rule, which is where templates fail first
The invoice number has to be a consecutive serial, unique within the financial year, not more than sixteen characters, and made only of letters, numbers, hyphens and slashes. One series, or clearly separated series if you genuinely need more than one — but each consecutive in itself.
A file cannot enforce any of that. The number is typed, which means it can be repeated, skipped or quietly rolled back when yesterday's invoice is edited into today's. A duplicate is not found at billing time; it is found at return time, in the month after the one it happened in.
The other half of the rule is that a cancelled invoice keeps its number. Deleting the row and reusing the number leaves a gap in your books and a figure in your customer's, and reconciling that is a long afternoon.
This is the single most practical argument for a system over a file, and it has nothing to do with features.
What goes wrong between the file and the return
The return is where billing errors become visible, and they arrive in a predictable order.
Place of supply recorded wrong, so a supply is reported in the wrong state and the tax head is wrong. A missing customer GSTIN, which silently moves a B2B supply into the B2C summary where it cannot be claimed. HSN codes left blank on some lines, so the summary table cannot be built. A combined tax figure that has to be unpicked line by line. And duplicated or missing invoice numbers, which is the one that takes longest to resolve.
None of these is hard to avoid at the moment of billing. All of them are expensive to fix a month later, because by then the customer has their copy and may have filed against it.
That asymmetry — cheap to prevent, costly to correct — is the real case for capturing an invoice properly the first time.
Credit notes, debit notes, and fixing a wrong invoice
An issued tax invoice is not something to edit. If the value was too high, or goods came back, the correction is a credit note that references the original invoice. If it was too low, a debit note. Both carry their own numbers and both appear in your return.
There is a deadline on the credit note that matters: the adjustment has to be declared by the return for the relevant month of the following financial year, or by the annual return, whichever comes first. Past that, the note exists commercially but the tax cannot be adjusted.
Software that lets you quietly retype an invoice raised last month is not doing you a favour.
Reverse charge, exports and the supplies that behave differently
Not every supply is a straightforward taxable sale. Some notified supplies put the tax liability on the recipient rather than the supplier. Exports and supplies to an SEZ can be made under a bond or LUT without payment of tax, or with tax and a refund claimed afterwards. Composition dealers cannot charge tax at all and must say so on the bill.
Each of these changes what the invoice has to say — the reverse charge marking, the LUT reference, the "composition taxable person" declaration. They are not exotic cases; most businesses hit at least one.
The fields are on the invoice in Billixo whether or not you use them, so the day you need one you are not looking for a workaround.
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.
The price, plainly
Free is ₹0 and stays ₹0. The paid plans are bought for a fixed term, paid once, with no auto-renewal and no card kept on file — when a term ends the account drops back to Free until you decide to buy again.
There is no per-invoice charge, no per-user surprise on the free plan, and no feature that is technically included but practically throttled. What the plan says you get is what you get.
Compare the plans on the home page, or just start free now and look at the ceiling from the inside.
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
Will my existing invoice numbers carry on?
Yes. You set the number the series should continue from when you start, so there is no gap and no restart in the middle of a financial year. That is usually the first thing to get right when moving off a file.
Can I get my data back out?
Yes, on every plan including the free one — CSV, Excel and JSON. Records you cannot export are not records you own, so this is not a paid feature.
Is a template invoice legally valid?
A document is valid if it carries the content the law requires, whatever produced it — a printed book, a spreadsheet or a system. The format is not the issue; the missing fields are. Most free templates are short of place of supply, an HSN or SAC per line, or the tax heads shown separately, and any one of those makes the document deficient.
Is it really free?
Yes. The Free plan is ₹0, needs no card and has no expiry. It has volume limits and leaves out the paid conveniences — watermark-free PDFs, GST return exports, the AI features, extra logins — but the invoices it produces are real GST invoices, and you can export your data from it whenever you like.
Do I need to install anything?
No. It runs in a browser, on a laptop, desktop or phone, so there is nothing to install, nothing to update and nothing tied to one machine. If the office computer dies, you sign in from another one and everything is there.
See it working on your own bills
The fastest way to judge billing software is to bill with it. Photograph one supplier invoice, raise one sales invoice, and look at the PDF your customer would receive.
Open the software demo → — free account, no card, about a minute to set up.
More details on the home page → — what it does, what it costs, and where the limits are.
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