the following link is related to Foreign Students to be Required to Subscribe to National Health Insurance.
http://world.kbs.co.kr/service/news_view.htm?lang=e&Seq_Code=158943

Foreign students who remain in Korea for six months or longer are required to subscribe to the national health insurance policy from March 1. 2021

Therefore, corporation for national health insurance(h-well NHIS) has provided information on the notification schedule and payment method for insurance.