Every tax payer (supplier) have to filled and submit Tax Invoice in Form Inv-1 format under GST Rule 5.
After submitting Form INV-1 , Supplier will get Invoice Reference No. from GSTN which is valid for 30 days. Invoice Reference No. will be used in Uploading Sales data to GST.
Please find below FROM INV-1 Format as per DRAFT GOODS AND SERVICES TAX -INVOICE RULES published on http://www.cbec.gov.in/htdocs-cbec/gst/draft-rules-format.
Hope, this will helpful post for GST Users.