See here: https://www.sss.gov/register/who-needs-to-register/#p1. Essentially, U.S. citizens and green card holders need to register but there are other groups as well.

Thanks, could someone give some clarity? The link to the details is 404. But, I found an old version on archive.org.

https://web.archive.org/web/20240516075853/https://www.sss.g...

Seems to suggest that F-1 student, H-1B temporary worker, visitor do not have to register. Is that correct?