The Central Board of Indirect Taxes and Customs (CBIC) issued 6 digit Services Accounting Code (SAC) for the classification of services.
The Annexure can be accessed at: https://www.cbic.gov.in/resources//htdocs-cbec/gst/Scheme%20of%20Classification%20of%20Services%20-%20amended.pdf;jsessionid=7A2001301280896708ED58B99F183C3E