The process at a glance
The billing process is the chain that turns a confirmed sale into money in the bank and a voucher in the books. In a well-run Indian SME it has six stages: a source document (an accepted order or a completed dispatch), an invoice raised against that source, GST and charges applied automatically, the invoice issued with e-way-bill data at hand, the payment received and booked against it, and the whole set posted to the accounts as vouchers. Two cross-cutting rules keep the chain honest: the invoice is a financial event that never moves stock, and every quantity can be billed once and only once.
If you are still weighing whether this belongs in software at all, the benefits guide makes that case; the pillar, what is GST billing software?, covers the surrounding concepts.
Stage 1 — the source: order accepted, goods dispatched
Billing does not start with the invoice; it starts with the document the invoice will be raised against. In practice that source is one of two things: an order acceptance — the confirmed commercial commitment recording what was agreed, at what rates — or a completed dispatch, the delivery challan on which goods physically left the premises. In a dispatch-linked deployment, stock has already moved out at this step; the warehouse side of that story is the challan's job, covered in delivery challan vs tax invoice.
This is the stage most manual processes skip — the invoice is typed fresh, with no live link back to the source. Everything that goes wrong later (double bills, missed bills, rate mismatches) traces back to that missing link.
Stage 2 — raise the invoice against the source
The operator opens a new invoice, picks the party, and selects the source dispatch or order. The item lines pre-fill from the source — items, quantities, rates — rather than being typed. Two protections engage at this moment:
- The used-quantity guard. The system tracks, per dispatch line, how much has already been invoiced, and offers only the un-invoiced remainder. A dispatch of 100 units with 60 already billed can only be billed for 40 more — the double-billing guard in action.
- The reference chain. Every invoice line carries an "against dispatch" or "against order" reference back to its source, so reconciliation — and, if ever needed, cancellation — is precise rather than forensic.
Part-billing is normal, not an exception: one dispatch may be billed across several invoices, or several dispatches consolidated onto one, and the guard arithmetic holds either way. Domestic invoices and export variants (where GST is suppressed or zero-rated under LUT, as configured) follow the same mechanics — the document types are catalogued in types of billing documents.
Stage 3 — GST, charges, rounding, amount in words
With the lines in place, the financial layer is computed, not typed. Each item brings its HSN code and GST rate from the item master (bulk-imported once, not looked up per bill). The buyer's GSTIN and state decide the split: CGST plus SGST for an intra-state sale, a single IGST for inter-state. Configured charge heads — freight, packing, insurance, loading — attach to the invoice with their own tax treatment. The total is rounded, and rendered as amount in words in Indian numbering. The operator's contribution to all of this is zero, which is precisely the point: compliance by construction, as detailed on the GST Tax Invoicing feature page.
Stage 4 — print, send, and the e-way bill
The confirmed invoice is printed as a formatted GST tax invoice or emailed to the customer directly. Where goods movement needs an e-way bill, the data required for it — items, values, transport details — is available from the invoice and dispatch details rather than assembled by hand; see GST, e-Way Bill & e-Invoice for how the compliance surface connects. For counter sales the same stage looks different — a thermal receipt in seconds at a POS counter — but the underlying document engine and tax masters are the same.
Stage 5 — payment, receipts and advances
An invoice is not the end of the process; it is the start of the receivable. The receipt entry books the customer's payment against one or more specific invoices — not as a loose credit — so the party's outstanding position stays true invoice by invoice. Advances get first-class treatment: money received on account before billing is applied to invoices as they arise, and only the balance remains outstanding. From here, ageing reports show who owes what and for how long, and overdue accounts get systematic follow-up over WhatsApp, email and SMS. The full receivables toolkit lives on the Payments, Receipts & Follow-up page.
Want to watch the whole chain run once?
Dispatch picked, invoice raised against it, GST computed, receipt booked, voucher posted — a 30-minute demo covers the entire process on your own items.
Stage 6 — returns, corrections and cancellations
Real processes have a reverse gear. Three formal mechanisms handle it without ever editing a posted invoice:
- Credit note on sales return — raised automatically when returned goods come back, against the original dispatch, reversing the invoiced value and its GST so the customer ledger corrects itself.
- Debit note — for the opposite direction: an under-charge, a rate difference in your favour, or an extra charge recovered after the invoice.
- Invoice cancellation — voids the whole document into a cancelled state and, crucially, releases the dispatched quantity it had consumed, so the dispatch can be re-billed correctly instead of being stranded half-billed.
All three are covered in depth in the Credit & Debit Notes feature and the document types guide.
Stage 7 — posting to Tally
The final stage is the quiet one: every finished document posts to the accounts as its matching voucher. The tax invoice becomes a sales voucher with CGST/SGST/IGST on the correct ledgers; the receipt becomes a receipt voucher; credit and debit notes become Cr/Dr notes; an approved supplier bill becomes a purchase voucher. Tally remains the book of record — the billing process simply keeps it fed, current and re-keying-free. Why this division of labour is the right one is the whole subject of billing software vs accounting software; the product mechanics are on the Tally Integration page.
Where the process breaks in real businesses
| Break point | What it looks like | The process fix |
|---|---|---|
| Invoice typed from scratch | Rates and quantities disagree with the order; disputes at payment time | Lines pre-fill from the order or dispatch reference |
| Dispatch billed twice | Angry customer, credit note, GST correction cycle | Used-quantity guard locks already-billed quantities |
| Dispatch never billed | Silent revenue loss found months later, if ever | Order-vs-invoice pending-to-bill report |
| Wrong tax split | CGST/SGST charged on an inter-state sale, or vice versa | Split decided from the buyer's GSTIN and state |
| Advance forgotten | Customer chased for money already paid | Advance adjustment inside the receipt entry |
| Books lag operations | Month-end re-keying marathon; books disagree with reality | Automatic voucher posting to Tally |
The project-billing variant
Firms that bill work rather than goods — construction, EPC, fabrication, job-work, services — run the same process with one substitution: the source document is a project and its bill-of-resources instead of a dispatch. Bills are raised against the project's resource consumption or progress — labour, machines, materials, milestones — with the same GST computation, the same amount-in-words output and the same posting to the books. The Project & Resource Billing feature and the construction industry page cover this mode; everything else on this page applies unchanged.
The process in Fast Billing Software
Fast Billing Software implements this exact chain — it is the process this guide is drawn from, running live in Indian manufacturing, engineering and trading deployments:
Frequently asked questions
What are the steps in the billing process?
Six stages: a confirmed source document exists (an order acceptance or a completed dispatch); a tax invoice is raised against that source, billing only un-invoiced quantities; GST and charges are applied — HSN, CGST/SGST or IGST, freight and packing, rounding and amount in words; the invoice is printed or emailed, with e-way bill data available from the invoice and dispatch details; the payment is recorded as a receipt against the invoice, adjusting any advance; and the finished documents post to the accounts as vouchers with GST.
Why should an invoice be raised against a dispatch or order?
Because the dispatch is the operational truth of what actually left, and tying the invoice to it guarantees the bill matches reality. Lines pre-fill from the source instead of being typed; a used-quantity guard blocks anything already invoiced, preventing double billing; and a pending-to-bill report shows dispatches and orders not yet invoiced, preventing missed revenue. An invoice raised from a blank screen has none of these protections.
Does raising an invoice reduce stock?
No. Stock moves at the dispatch step, when goods physically leave on a delivery challan. The invoice is a financial event: it attaches commercial value and GST to material that has already gone. This separation is deliberate — it lets goods ship on one rhythm and billing run on another, and it is why billing software uses a used-quantity guard, rather than a stock movement, to enforce billing integrity.
How are advances handled in the billing process?
An advance is money received before the invoice — common in project work and made-to-order manufacturing. Good billing software books it on account against the party, then adjusts it when invoices are raised: the receipt entry applies the advance to the invoice, and only the balance remains outstanding. This keeps the party ledger true and prevents chasing a customer for an amount their advance already covers.
What happens after the invoice — how does it reach Tally?
Each finished document posts as its matching voucher: the tax invoice as a sales voucher with CGST/SGST or IGST on the right ledgers, the receipt as a receipt voucher, credit and debit notes as Cr/Dr notes, and approved supplier bills as purchase vouchers. Ledgers are mapped once, so posting is automatic and nothing is re-keyed. Tally stays the book of record.
What if goods come back after the invoice is raised?
A sales return triggers a credit note against the original dispatch and invoice, reversing the billed value and its GST so the customer ledger stays correct. If the entire invoice must be voided, a cancellation converts it to a cancelled state and releases the dispatched quantity it had consumed, so the dispatch can be re-billed correctly. Both flow to the accounts, keeping books and GST returns aligned with reality.