Nuxt/docs/content/2.app/1.app.md

App.vue

The new app.vue file, is the main component in your Nuxt3 applications.

If you would like to customize the global website entrypoint, you can create app.vue in your project directory. Nuxt will automatically detect it and load it as the parent of all other pages within your application. This will be primarily useful for adding code that should be run on every single page of your site (see page layouts creating dynamic layouts).

Note: Don't forget to use <NuxtPage> component somewhere inside app.vue.

<template>
  <div>
    <NuxtPage />
  </div>
</template>