If you're selling ready-made clothes via e-commerce platforms like Amazon or Flipkart, even with a turnover below 20 lakhs, GST registration is mandatory. This is because you'll likely be selling goods to customers in different states. You cannot trade as an unregistered vendor on these online marketplaces.
16 February 2020
Registration of seller thru e-commerce is not mandatory w.e.f.01 Feb 2019
GST Registration is now mandatory only for e-commerce operators who are liable to collect tax at source, as against the earlier provision of every e-commerce operator.
16 February 2020
Since you will be selling goods via online e-commerce portal, you will be selling goods to to outside states also, you shall have to take GST registration mandatorily even though your turnover is less than 20 lakhs (new limit is 40 lakhs) You wont be able to sell as unregistered vendor on e-commerce portal.