Two documents, two situations
Most people think of one bill. Under GST there are two. A tax invoice is for taxable supplies. A bill of supply is for registered persons whose supply is exempt, or who pay tax under the composition scheme. Giving the wrong one is a common mistake in a small business that has just registered.
What the Act says
Section 31(3)(c) of the CGST Act says a registered person who supplies exempted goods or services or both, or who pays tax under Section 10 (the composition scheme), shall issue a bill of supply instead of a tax invoice. A registered person who supplies taxable goods or services issues a tax invoice under Section 31(1) and (2).
What goes on a bill of supply
Rule 49 lists the contents. Supplier name, address and GSTIN. A consecutive serial number of up to sixteen characters, unique for the financial year. The date. The recipient's name, address and GSTIN or UIN if registered. The HSN code. A description of the goods or services. The value of the supply after any discount or abatement. And the signature or digital signature of the supplier or his authorised representative, although an electronic bill of supply issued under the Information Technology Act does not need a signature.
Composition scheme: no tax on the bill
Section 10 says a person paying tax under the composition scheme shall not collect any tax from the recipient, and cannot claim input tax credit. So a composition bill of supply must not show GST charged to the customer. If your CA has put you on the scheme, never add a GST line to the bill, and check that your billing software does not do it automatically.
The 200 rupee exception
Both Section 31(3)(b) and 31(3)(c) say a registered person may not issue the bill if the value of the supply is less than two hundred rupees, subject to conditions and in the prescribed manner. The conditions matter. Do not assume small sales need no bill: ask your CA what you must still record, such as a daily summary, and do not skip a bill when a customer asks for one.
What to do (our advice)
Ask your CA one question: under which section is each of my supplies, taxable, exempt, or composition? Then set up two bill formats if you need them, check the serial number never repeats in a financial year, and keep one short checklist at the billing counter. If some of what you sell is taxable and some exempt, say so to your CA, because the bill type depends on each supply.
Ask your CA which bill each of your supplies needs, then fix your billing format.
How this post was made: an AI drafted it from the official pages listed under Sources, every figure was checked against those pages, and the Reveaxa team approved it before it was published. Our own advice is marked as such. If a source changes, we update the post and its date.
Reveaxa guide reference: RVX-B-gst-bill-of-supply-vs-tax-invoice