To know what is CGST, SGST and IGST we need to know what is Intra-State supply of goods and Inter-State supply of goods.
Intra-State supply of goods means seller and buyer locations are in same state.In this Intra-State supply manufacturer will collect both SGST and CGST from end user.CGSt goes to Central Government and SGST goes to State Government.
Inter-State supply of goods means seller and buyer locations are in different states.In Inter-State transaction a manufacturer will collect IGST from user.IGST goes to Central Government.
lets take an soap manufacturer in Andhrapradesh supplies soap worth Rs.20,000 to Telangana, For this export manufacturer charge CGST 6% and SGST 6 % on product value. means Rs.1200 was depoisted in central government as well as state government.
lets take an soap manufacturer in Andhrapradesh supplies soap worth Rs.20,000 to kadapa, For this one manufacturer charge IGST 12% on product value.The manufacture deposit Rs.24,000 in central government.