What are the mandatory fields in a GST invoice?

Rule 46 of the CGST Rules requires 16 mandatory fields on a GST invoice, including the supplier's name, address, and GSTIN, a unique sequential invoice number, the invoice date, the buyer's details, HSN or SAC codes, item description, quantity, taxable value, the tax rate and amount split into CGST, SGST, or IGST, the total invoice value, and the supplier's signature or digital signature. Missing even one of these fields can render the invoice non-compliant and block the buyer's input tax credit claim. Billoxy's GST Invoicing Tool auto-populates and validates all 16 mandatory fields before an invoice is sent, so compliance is checked automatically.