In order to find the npm latest stable version, you need to visit the npm documentation web page and check the footer.
Earlier it used to mention the version number in footer but now it provides a link to the GitHub hosted repository https://github.com/npm/cli/releases/latest; so, you can directly check go to this link and check the latest stable npm version available.
If I am beginner with npm, then this question will definitely come to my mind. To get an answer to this, you should ask the following questions to yourself:
If you are going to include the package (say “slick-carousel”) using statement like “require” in node.js and then use it in your module.
npm install <package_name>