In accordance with Notification No.78/2020 - Central Tax dated 15th October 2020, taxpayers must provide 6-digit HSN Codes for their outward supplies having AATO(Annual Aggregate Turnover)
more than Rs 5 Crores. The Indian e-Invoice System will not accept 4-digit HSN codes in a few weeks' time. Taxpayers are advised to adjust their systems to report 6-digit HSN codes to the e-Invoice Portal and comply with the upcoming notification.
Taxpayers may verify all the HSN codes in the ( https://einvoice1.gst.gov.in ) portal under Search->Master->HSN Codes and also test in the sandbox system ( https://einv-apisandbox.nic.in ). It is possible to raise a ticket at Helpdesk in case the 6 digit HSN code is not available.