What is a GST invoice?
A GST invoice (tax invoice) is a document a registered seller must issue for taxable goods or services. It must contain specific details required by GST law.
Mandatory fields
- Seller name, address and GSTIN
- Invoice number and date
- Buyer details and GSTIN (for B2B)
- HSN/SAC code for each item
- Taxable value, and CGST + SGST (same state) or IGST (other state)
- Total amount in words
CGST/SGST vs IGST
Same state = CGST + SGST (half each). Different state = IGST (full). Good billing software does this automatically based on the place of supply.