[HELP] How to make a wordpress post/page into HTML

As the title says,

How to make a wordpress post/page into HTML website?

I found a wordpress website (sorry I can't post the links, I don't want to destroy the guys work) were it has an HTML website as its post/page. I don't know how did he do it. I did search google, but I can't find any tutorial.

I can PM the website if someone is willing to help. Thanks!

I know that you can add HTML as part of your main domain and add Wordpress to a subdirectory and I'm sure that through PHP you can get what you want.

He has a pure HTML pages within Wordpress engine? Or some pages on server like site.com/demo.html? By default I would have a look to page source code, copy it and sift it.

You can add HTML in wordpress post. But actually i don't really know what do you mean?