Since from 1st April 2021 it is important for the GST assessee who posses the turnover exceeds 5 cr in the before fiscal year, to file 6 digits HSN Code (Harmonised System of Nomenclature Code), or as the case may be, SAC (Service Accounting Code) upon the invoices provided for the supplies of taxable goods and services.
The assessee who has the turnover of Rs 5 cr in the previous financial year is needed to file 4 digits HSN code on business to business (B2B) 
A helpful GST guide for consumers, B2B (Business to Business) and B2C (Business to Consumer) by SAG Infotech. We also included some important GST articles. read more invoices. Before that, the need was 4 digits and 2 digits correspondingly. For more information notification No. 78/2020-Central Tax, dated 15.10.2020.
The GST assessee will need to file HSN/SAC in their invoices according to the amended need wef 1/04/2021. HSN codes for the goods at 6 digits are common for everyone. Thus common HSN codes apply towards the customs and GST. as per the codes mentioned in the customs tariff are used for the intention of the GST as this has been particularly provided in the GST rate schedule.
In the customs tariff, HS codes are mentioned as a heading 4 digit HS, subheading 6 digits HS), and charge items 8 digits. All these credentials are accessible on the CBIC website. The rates of customs might be accessed for HSN codes.
GST rate schedule for the goods and services 
Get to know GST provisions and rules on the free supply of goods. Also, we have included rules regarding ITC reversal on free supplies of goods and services might be accessed and then track the path GST rates or ready reckoner-updated notifications or find the GST rates ready reckoner or updated notifications. Moreover, the HSN search facility is to be open on the GST portal.
The HSN codes are now being commonly used by Manufacturers and importers/exporters. The manufacturers were filing these codes even in the pre-GST regime. The importers and exporters are filing these codes in the import or export credentials.
The traders will mostly use HSN codes in filing the invoices provided to them through the manufacturer or importer supplies. Various GST assessees are “already filing the HSN Codes/SAC at 6/8 digits on a voluntary basis on the invoices, e -waybills, and GSTR 1 returns.”
