Can I opt-in for composition scheme anytime during the year? No. Before the beginning of every financial year, a registered taxpayer is required to provide a declaration on the GST Portal. This cannot be done anytime during the year.
yes , you can opt composition scheme but for opting it is not possible for this FY 2018-2019, as it is closed on 31sr March 2018. if you can opt composition scheme for next FY 2019-2020 at the last month(March) of FY 2019.
Yes you can opt for Composition Scheme ( SECTION 10 of CGST Act 2017 ) from Regular Scheme if you satisfy the conditions laid down u/s 10(2) of CGST Act 2017.
But to opt in for Composition Scheme, you have to wait for March 2019 and opting for Composition Scheme for FY 2018-19 has been closed...