For every page you can inject elements into the page head. This way you can add stylesheets, JS scripts, meta tags, a custom title or whatever you think is convenient to add inside the <head> of your page.
This example shows in pages/index.js how to add a title and a couple of meta tags.
Deploy the example using Vercel:
Execute create-next-app with npm or Yarn to bootstrap the example:
npx create-next-app --example head-elements head-elements-app
# or
yarn create next-app --example head-elements head-elements-appDeploy it to the cloud with Vercel (Documentation).