GSTR-3B filing deadline set monthly with payment required via electronic cash or credit ledger by the filing due date. The return in FORM GSTR-3B for each month of the specified quarter shall be furnished electronically through the common portal on or before the twentieth day of the month succeeding such month, and every registered person furnishing that return must discharge tax, interest, penalty, fee or any other amount by debiting the electronic cash ledger or electronic credit ledger, as applicable, not later than that last date.