How will the goods and services be classified under GST regime?

HSN (Harmonised System of Nomenclature) code
shall be used for classifying the goods under the GST regime.
Taxpayers whose turnover is above Rs. 1.5 crores but below
Rs. 5 crores shall use 2 digit code and the taxpayers whose
turnover is Rs. 5 crores and above shall use 4 digit code.
Taxpayers whose turnover is below Rs. 1.5 crores are not
required to mention HSN Code in their invoices.

Services will be classified as per the Services Accounting
Code (SAC)