what does npm install package? code example

Example 1: how to install latest version of npm package

//For global packages 
npm i -g <package name>@latest
npm i -g express@latest

//For loacal packages
npm outdated
npm update

//Manually updating local packages
npm i <package name>@latest
npm update "react" "react-dom"

Example 2: what is npm install

npm install module-name
npm i module-name
puts module-name package (js library file) 
into node_modules folder
so you can require it in node app