As a GST composition scheme registered taxpayer, you are required to file the following returns:

1. GSTR-4: This is a quarterly return that must be filed by the 18th of the month following the end of the quarter. This return contains details of your sales, purchases, and tax liability.

2. Annual return GSTR 9A: This return must be filed once a year by 31st December of the following year. It contains a summary of your sales, purchases, and tax liability for the entire financial year.

Note that as a composition scheme registered taxpayer, you are not required to file monthly returns such as GSTR-1, GSTR-3B or even GSTR-9. However, you are required to pay taxes quarterly at a fixed percentage of your turnover, and file GSTR-4 accordingly.