Non-resident taxpayers must file GSTR-1, GSTR-2, and GSTR-3 within seven days after registration ends.
Casual or non-resident taxpayers are required to file GSTR-1, GSTR-2, and GSTR-3 for the duration of their registration within seven days after the registration expires. If the registration period exceeds one month, monthly returns must be filed, followed by a return for the remaining period within the same seven-day timeframe.