TDS under GST: DDOs must register in GSTN, generate challan with CPIN and remit via RBI before bill payment. DDOs must register in GSTN as tax deductors, generate a GSTN challan and record the CPIN before bill preparation; classify GST components, remit by NEFT/RTGS to the Reserve Bank of India, and add the RBI IFSC and CPIN as a beneficiary entry in bill-generation applications (BiMS, EMLI, SANKHYA). Submit the bill to treasury with the challan copy; on passing, treasury remits the TDS to RBI and updates the DDO's GST ledger. File the prescribed return monthly and ensure bill encashment within the challan validity period.