Publish a static site
A static site is a folder of files the browser can open: HTML, CSS, JavaScript, and images. Build the site on your machine first, then upload that folder from New project.
Name the site with 2 to 40 characters. The name becomes the public link. If you already own that name, publishing again updates the same site instead of creating a second one.
You can also upload a zip of the built folder. Keep the upload under the size limit shown in the form. The panel does not compile a framework for a static upload. It serves the files you give it.
Static sites still get deployment logs, environment variables, and usage on the project page. A new publish is how you ship the next version of the files.