HSN code in GSTR 1 in 2021-22

Yes it is required to enter HSN Code details in GSTR-1 from 1st April 2021

Please refer to the following notification

With effect from the 1st April, 2021, it has been made mandatory for a GST taxpayer, having turnover of more than Rs 5 crore in the preceding financial year, to furnish 6 digits HSN Code (Harmonized System of Nomenclature Code), or as the case may be, SAC (Service Accounting Code) on the invoices issued for supplies of taxable goods and services. A taxpayer having turnover of upto Rs 5 crore in the preceding financial year is required to mandatory furnish 4 digits HSN code on B2B invoices. Earlier, the requirement was 4 digits and 2 digits respectively. For more details, notification No. 78/2020-Central Tax, dated 15.10.2020 may be referred to (accessible at https://www.cbic.gov.in/resources//htdocs-cbec/gst/notfctn-79-central-tax-english-2020.pdf)

Yes in this case 4-digit HSN code should be mentioned in GSTR-1 as well

In the order it is not mentioned about GSTR-1 , everything said is w.r.t Invoice only

Yes HSN code is required to be provided in GSTR-1 filing