HTTPS adds a layer of encryption that prevents others from snooping on or tampering with traffic to your site. You can enforce HTTPS for your GitHub Pages site to transparently redirect all HTTP requests to HTTPS.| GitHub Docs
You can set up or update certain DNS records and your repository settings to point the default domain for your GitHub Pages site to a custom domain.| GitHub Docs
GitHub Pages supports using custom domains, or changing the root of your site's URL from the default, like octocat.github.io, to any domain you own.| GitHub Docs