Quick Bio Link pages are entirely self hosted. But there are many free tier and low cost options available for hosting your page. Below you'll find a few common options. Not seeing your preferred host? Create a tutorial and PR or create na issue to request a tutorial be made.
Cloudflare Pages allows you to deploy sites to the edge. The free tier includes unlimited sites, requests, and bandwidth. Learn how to get started and how to deploy static sites.
Digital Ocean's app platform allows you to deploy 3 static sites for free. When changes are made to a GitHub repository it automatically redeploys making it an excellent free option for hosting Quick Bio Link pages.
Step by step guide/tutorial: Guide for customizing Quick Bio Links pages, uploading to GitHub, deploying to Digital Ocean's App Platform, and point domain with CloudFlare by Mackenly Jones (project maintainer)
Read the documentation: App Platform Static Site Documentation
Follow this Firebase guide to learn how to deploy your site to Firebase hosting. The free plan allows 1 GB of files and 10 GB/month transfer.