Create html from Pages?

Not directly no. Pages does not support HTML directly for file export.

You can export the document a Word doc and then use any number of apps to convert that to HTML.

See here: Save Pages file as HTML? - Apple Community

You don't. Pages has no HTML export, or save feature, but MS Word and LibreOffice Writer do, if you were to feed them a Pages document exported as Word .docx document.

If you had the optional, free Pandoc command-line tool, you could convert a Word .docx document (without images) to a formatted HTML document. Pandoc also supports including a CSS (.css) style document to enhance the HTML result:

pandoc -s -t html5 --metadata title="a foo title" -o foo.html foo.docx
open foo.html

Pages is not an html editor. Text edit is not either, but it is closer to being one in that it can work in Rich Text format, which may be more easiky reformatted into html.

There are several online sites offering web page generation tools, and I suspect there are several html editing applications in the Mac App store.

Regards,

Barry