Quotation to invoice: the document chain of every sale
A sale is a series of promises, and each document in the chain fixes one promise in writing: what we offered, what you ordered, what we shipped, what you owe. Businesses that skip links — quote on WhatsApp, deliver from memory, invoice "when we get time" — don't save effort; they move the effort into disputes. Here is each document's actual job.
The chain, in order
| Document | Its promise | Binding? |
|---|---|---|
| Quotation | "This is our price, valid till this date." | An offer — binding once accepted within validity. Undated, open-ended quotes haunt you at last year's prices. |
| Proforma invoice | "This is exactly what the bill will look like" — often used to collect advance payment. | Not a tax document. No GST liability arises, no ITC flows from it. It looks like an invoice; it is a preview. |
| Sales order | "We accept your order on these terms" — the customer's PO confirmed. | The contract's operational form; what stock gets reserved and production gets planned against. |
| Delivery challan | "These goods left our premises" — for transport, job-work, branch transfers, approval goods. | Moves goods; does not transfer money. Sales on challan must still be invoiced. |
| Tax invoice | "You owe us this, and here is the GST on it." | The legal heart of the sale — liability for you, ITC for the buyer, the entry for GSTR-1. |
| Credit / debit note | "The invoice changed" — returns, shortages, rate corrections. | The only legitimate way to shrink or grow an issued invoice. |
| Receipt | "Your payment arrived and was set against these bills." | Closes the loop; unadjusted receipts are how ledgers rot. |
What GST law fixes about the invoice
- Timing: for goods, the invoice must exist at or before removal/delivery; for services, within 30 days of providing the service. "We'll bill at month-end" is a habit, not a rule — and for goods in a truck it is an illegal one.
- Contents: the rules prescribe them — your GSTIN and the buyer's, a consecutive serial number unique to the year, date, HSN/SAC, quantities, taxable value, rate and tax split (CGST/SGST or IGST), place of supply, signature. Registered buyers' invoices missing these fields cost them credit and you goodwill.
- Serial discipline: numbers must run in sequence, and the year's used-and-cancelled ranges are reported in GSTR-1's documents table. A gap with no cancelled invoice behind it reads as a sale kept off the books.
- Small B2C mercy: a consolidated daily invoice is allowed for small unregistered-buyer sales below the notified value — the reason a retail counter isn't buried in paper.
- Above the e-invoicing threshold, the tax invoice also needs its IRN and QR code to be valid at all.
Where money leaks between the links
- Quote → order: quotes that die silently. Nobody follows up, nobody records why it was lost — a follow-up system is the fix, and "lost: price" ten times is pricing feedback you paid for and threw away.
- Order → delivery: goods dispatched that were never ordered in writing, or partially delivered orders nobody tracks. The balance quantity is real money with no owner.
- Delivery → invoice: the classic leak — challans that never became invoices. Every unbilled challan is stock gone and revenue not booked.
- Invoice → payment: invoices with no due date, receipts never knocked off against bills, and an outstanding list nobody trusts enough to act on.
💡 The conversion test: pick any month and ask — how many quotations became orders, how many challans are unbilled, how many invoices are past due? If any of the three takes more than a minute to answer, the chain has gaps, and the gaps are where your margin goes. A healthy system answers all three from one screen.
How Arthora does this: Arthora CRM runs the front of the chain — leads, quotations, follow-ups, won/lost reasons — and Arthora ERP runs the rest: sales orders, delivery challans that convert to invoices (so nothing ships unbilled), GST-complete tax invoices with serial discipline, e-invoice and e-way bill from the same entry, and receivables that show exactly who owes what since when. Each document converts into the next — typed once, promised once.
A chain with no missing links
Quotation to invoice to payment — Arthora CRM and ERP keep every promise in writing. 7-day free trial, no card.