Filing GST returns is mandatory for companies that are GST-registered in India. The GST Returns Due Date differs based on the kind of return. For instance, GSTR-1 for departing supplies is due on the eleventh of the next month, whereas GSTR-3B, a summary return, is often due on the twentieth. Taxpayers file GSTR-1 quarterly and make monthly tax payments under the QRMP plan. Timely filing guarantees seamless GST compliance and helps prevent penalties.