npm tag <name>@<version> [<tag>]
Tags the specified version of the package with the specified tag, or the --tag config if not specified.
A tag can be used when installing packages as a reference to a version instead of using a specific version number:
npm install <name>@<tag>
When installing dependencies, a preferred tagged version may be specified:
npm install --tag <tag>
This also applies to npm dedupe.
Publishing a package always sets the “latest” tag to the published version.