- https://manpages.debian.org/unstable/passwd/vipw.8.en.html
- https://manpages.debian.org/unstable/passwd/vigr.8.en.html
- https://manpages.debian.org/unstable/sudo/visudo.8.en.html
vipw and vigr are actually the same utility.
You still have to also apply sudo on your command in order to gain the necessary privileges:
$ sudo vipw
Under certain circumstances you have to tell the utility, which (visual) editor to use:
$ sudo VISUAL=vim vipw
CAVEAT: the following article tells you something incorrect regarding “-s” / “–shadow” (read it up on the manual page referred to above and also on the article’s own comments section!):