Your GST registration
Where the buyer is
You should issue
Tax invoice
GST shown as CGST + SGST, split equally.
Buyer's GSTIN and registered name filled from the GST registry.
Tax invoice: you're registered under the regular scheme
This is the document that lets your buyer claim input tax credit, so it has the most rules. It must carry your GSTIN, a serial number of 16 characters or fewer that runs continuously through the financial year, the date, the buyer's name and GSTIN if they have one, the place of supply, each line's HSN or SAC code, quantity, taxable value, rate and the tax split. For services you have 30 days from the date of supply to issue it; for goods it goes out with the goods.
Bill of supply: you're under composition, or the supply is exempt
A composition dealer pays a flat tax on turnover and can't collect GST from customers, so the document has no tax column and must say so in print. Regular dealers also use a bill of supply for exempt or nil-rated items. If you sell both taxable and exempt lines to one buyer, a single "invoice-cum-bill of supply" is allowed.
Cash memo: you're not registered
Below the registration threshold you issue an ordinary bill. It's a receipt, not a GST document, so no GSTIN, no tax lines, and nothing to report. Your khata, stock and reports work exactly the same way, and the day you register, the same sales start producing tax invoices.
Same state or another state
The document doesn't change with geography; the tax does. Buyer in your state: the rate splits into CGST and SGST (UTGST in a union territory). Buyer in another state: IGST for the full rate. The buyer's GSTIN is what fixes their state, which is why the app looks up the registered name and state from the GSTIN before it prints anything.
What the app does with all this
You say "Verma Builders ka bill banao, 4 ton TMT 52,000 per ton". AawazAI reads your registration type, picks tax invoice, bill of supply or cash memo, fills HSN and rate from your catalogue, splits the tax by place of supply and shows you the card. You confirm, and the bill goes to the customer on WhatsApp. If you're under composition it prints the declaration; if you're unregistered it prints no GST at all. More on GST in the app.
Questions
Common cases
I'm registered under the composition scheme. What do I give my customer?
A bill of supply, not a tax invoice. You can't charge GST on it, and it must carry the words "composition taxable person, not eligible to collect tax on supplies". You pay tax on your turnover through CMP-08 instead.
I'm not registered for GST. Can I still issue a bill?
Yes, a plain bill or cash memo with no GST on it. Don't print a GSTIN you don't have or show tax you can't collect. Once your turnover crosses the registration threshold and you register, your bills become tax invoices.
My customer is in another state. What changes?
The document type doesn't change, the tax does: instead of CGST + SGST you charge IGST for the full rate, and the buyer's state code appears as the place of supply. Get the buyer's GSTIN right, because that is what decides their state.
Do I need a tax invoice for a ₹50 sale to a walk-in customer?
A registered dealer can issue a consolidated tax invoice at the end of the day for B2C sales below ₹200 where the customer does not ask for one. Anything the customer asks for, or any B2B sale, needs its own invoice.
Does a credit note need GST on it?
Yes. When goods come back or a price is reduced, a credit note reverses the tax you charged, and it is reported in GSTR-1 (as CDNR for registered buyers, CDNUR for unregistered). Cancelling an invoice outright is different: the number stays in your series and drops out of the return.