GSTR-1 is a monthly Statement of Outward Supplies to be furnished by all normal and casual registered taxpayers making outward supplies of goods and services or both and contains details of outward supplies of goods and services.
Every registered taxable person, other than an input service distributor / composition taxpayer / persons liable to deduct tax u/s 51 / persons liable to collect tax u/s 52 is required to file GSTR-1, the details of outward supplies of goods and / or services during a tax period, electronically on the GST Portal.
You can opt for quarterly filing of GSTR-1 return under following condition: If your turnover during the preceding financial year was up to Rs. 1.5 Crore; or if you are registered during the current financial year and expect your aggregate turnover during FY 2017-2018 to be up to Rs. 1.5 Crores.
Facility to change frequency is available if you have not filed any return during the financial year according to the original frequency.
GSTR-1 needs to be filed even if there is no business activity (Nil Return) in the tax period.