請問,移民簽證申請人的健康保險,是簽證前買還是登陸美國以後買?
-It seems this rule was suspended by a judge.
See:
https://www.wenxuecity.com/news/2019/11/03/8825444.html
Just contact NVC to see whether the health insurance is required for the immigrant visa application a couple of days later.