If it exceeds prescribed turnover yes. However, considering the fact that it is a pre requisite to register as suppilier with Amazon / Flipkart, get normal registration under GST
yes Section 22(1), CGST act 2017 creates liability for registration on every supplier in the state or UT from where he makes taxable supply of goods or services or both , if his aggregate turnover in a f.y. exceeds 20Lakh rupees.
Register as Normal/Regular Taxpayer. Registration in GST is mandatory if you sale your GOODS through E-COMMERCE operator like Amazon/Flipkart etc; in accordance with the Provision of Section 24.