Simply create ledgers related to purchases , before making purchase entry in Tally and the Tally add on feature takes care of the rest for you
You can implement this add on in both Local Purchases on which CGST and SGST and Interstate Purchase on which IGST.
Tally on cloud overcomes the problem of IT infrastructure
that needs to be mandatory with on-premise Tally.ERP 9 software. All it
requires to setup/host software on the cloud server.