Ask this site for Docusaurus

Add the script in your config, then put the box on any page.

docusaurus.config.js

export default {
  scripts: [{ src: "https://askthissite.com/embed.js", async: true }],
};

Any .mdx page

<div data-everypage-site="YOUR-SITE-ID"></div>

Your site id is on your site's page after you sign up.