Tax invoice or bill of supply
Which document your bills come out as, why the tax total will not match line-by-line arithmetic, and what happens to orders that arrive from a delivery partner.
One setting decides the document
Your GST registration type on the business profile is the only thing that chooses between the two documents. Nothing on the bill, the item or the customer can change it.
- Regular — every settled bill is a tax invoice, with GST charged and shown by head.
- Composition scheme or unregistered — every settled bill is a bill of supply, and no GST is collected. The document says so in as many words.
Changing the setting changes what comes out from that moment on. It does not rewrite documents already issued, and it should not: a document a customer has already been handed is a fact, not a draft.
Why the tax total does not match your own arithmetic
Tax is worked out once per invoice per head, not once per line. Every taxable line at the same rate is added together first, and the tax is computed on that combined base.
Take five lines at the same rate on one bill. Taxing each one and adding the results can differ from taxing the sum, by a paisa or two, because each of the five roundings goes its own way. Only the second method is correct, and it is what the product does, so a bill you check line by line on paper may land a paisa away from what is printed. The printed figure is the right one.
Where the rate splits into a state and a central half, both halves take the same base and each gets half the rate. An out-of-state supply carries a single combined head instead. Lines at zero or exempt produce no head at all — they still count towards what you sold, just not towards what you charged.
Compensation cess, where a dish attracts it, is a head of its own at its full rate and prints after the GST heads. It can appear on a line that carries no GST.
The rounding line
The grand total is rounded to the nearest whole rupee, and the difference between the rounded total and the true one is shown as a round-off. It is never quietly absorbed into a tax head, because the tax heads are what you remit and a rounding is not tax.
Orders that come from a delivery partner
An order that arrives from a connected delivery partner is tagged as one where the operator remits the GST, and the receipt says so in a line of its own. The product tags such orders; it does not charge GST on them. Nothing about it is a setting you turn on — an order that comes in through a partner connection is tagged automatically, and one you ring on the till is not.
This is also why your own total sales and your GST-charged total will not agree in a month with delivery in it, and why the export summary keeps aggregator value in a column of its own rather than folding it into your taxable value.
Where to check what was issued
The invoices list in the back office shows what each settled bill came out as. The GST summary report totals a period by head, and the export centre produces the return registers themselves. If a document type looks wrong for a period, the profile is where the cause is — check the registration type for that outlet, and for the date the bill was issued.