<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script> code example

Example 1: install vue js

npm install -g vue-cli    //make sure you have node and npm installed 
vue init webpack <appname>  //  eg:  vue init webpack myapp
cd <appname>               // cd myapp
npm install
npm run dev  //server will start in port 8080

Example 2: vuejs cdn

/*for development ===>*/ <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
/*for production ===>*/ <script src="https://cdn.jsdelivr.net/npm/[email protected]"></script>