How to Create a GST Invoice, Format and Mandatory Fields

A GST invoice isn’t just a receipt, it’s a legal document, and a return that doesn’t match your invoices is a return that gets questioned. The good news: the required format is fixed, so once you get it right, every invoice is right.

What a valid tax invoice must contain

A compliant GST tax invoice needs, at minimum:

• Your name, address and GSTIN
• A consecutive invoice number (unique, within a series)
• Date of issue
• The customer’s name, address and GSTIN (for B2B)
• HSN code (goods) or SAC code (services) per line
• Description, quantity and unit of each item
• Taxable value and any discount
• Tax rate and amount, split into CGST + SGST (intra-state) or IGST (inter-state)
• Place of supply for inter-state sales
• Whether tax is on reverse charge
• Signature (or digital signature) of the supplier

Miss the HSN code or the tax split and the invoice is technically defective, and it won’t reconcile against your GSTR filings.

Tax invoice vs bill of supply

• A tax invoice is what you issue when you charge GST.
• A bill of supply is for exempt goods or composition-scheme dealers who can’t charge GST. Same discipline, no tax line.

Using the wrong one is a common slip for newer businesses.

Invoice numbering, keep it clean

Numbers must be consecutive and unique within a financial year series. Gaps and duplicates are exactly what an audit looks for. Let the system generate them; don’t type them by hand.

The easy path

Every field above is either fixed (your GSTIN) or derived from the sale (items, HSN, tax split, place of supply). A billing system that holds your product catalogue with HSN codes and applies tax inside the engine produces a compliant invoice on every sale, no template to babysit, no field forgotten.

That’s the whole idea behind Piatto Pro’s billing: the invoice comes out right because the tax logic and the catalogue live inside it, for both India GST and UAE VAT.