Auto-population of e-invoice details into GSTR-1

For the month of March, 2021, the auto-population of e-invoices into GSTR-1 (of March, 2021) is still in progress and is likely to take some more time.
To check whether a HSN Code is valid or not, please visit GST Portal: www.gst.gov.in > Services > User Services > Search HSN Code
Additional FAQs on e-invoice released. The new version of FAQs can be accessed HERE . (Note: New additions and changes in this version are marked in blue).
For the benefit of taxpayers, a concise ready reckoner on e-invoice is released in English as well as Hindi. Please find the same here: https://www.gstn.org.in > Our Projects > e-invoice > At a Glance > e-invoice – At a Glance / e-invoicing – Ek Nazar Me