The short answer.
The free GST invoice generator creates tax invoices and quotations with seller and buyer GSTIN, HSN/SAC codes, and automatic CGST + SGST (same state) or IGST (inter-state) split. Add items, choose the GST rate, upload your logo and download a professional PDF. Everything runs in your browser.
What a valid GST tax invoice needs
The supplier's name, address and GSTIN, a unique invoice number and date, the recipient's name and address (and GSTIN if registered), HSN/SAC codes, the quantity and value of goods or services, the taxable value, the rate and amount of CGST/SGST or IGST, the place of supply, and a signature. This tool includes all of these fields.
CGST + SGST vs IGST
If the seller and buyer are in the same state, GST splits equally into CGST and SGST (for example 9% + 9% for 18%). If they're in different states, the whole rate is charged as IGST. The tool decides automatically from the state codes. Your draft is saved in your browser only.