HSN stands for Harmonised System Nomenclature is a code used for classifying the goods under GST Act. It is an internationally standardized system of names and numbers used to systematically classify goods all over the world. HSN is an 8-digit code.
While taking ITC on purchases and other expenses, kindly verify that supplier has mentioned HSN/ SAC code in invoice as required. If HSN/ SAC Code is not mentioned in invoice, then ITC will not be available.