npm install element-plus --save

npm install babel-plugin-component -D

//babel.config.js
module.exports = {
  presets: [
    ['@babel/preset-env', { 'modules': false }]
  ],
  'plugins': [
    [
      'component',
      {
        'libraryName': 'element-plus',
        'styleLibraryName': 'theme-chalk'
      }
    ]
  ]
}

import 'element-plus/lib/theme-chalk/index.css';
import { ElButton } from 'element-plus'
createApp(App).use(ElButton).mount('#app')