Site hosting, explained in one sentence
Site hosting should answer “where does this website live?” SiteHost’s answer: on our platform, at a URL you control, with a certificate you do not renew by hand.
A place to live
Every site gets an HTTPS address immediately. That is enough to share a draft. Production is the same site with your domain on it.
A way back
Publishing is not a one-way overwrite you cannot undo. Previous versions stay in history so a bad upload is recoverable.
Questions
Do I need to know what PHP is?
No. If you have ordinary website files, choose the regular website option. PHP is only for sites that run code on the server.