If you love the static .html style for your WordPress blog, you can add .html to the end of each blog post. This can be done by using a custom URL structure, for example /%category%/%postname%.html, in the Permalink Settings menu (Settings -> Permalinks). However WordPress lets you add this .html extension to posts only, you can’t find anywhere to set it for pages.
If WordPress doesn’t give you that function, why don’t you do it with the help of a plugin? There is a WordPress plugin that can help you do that easily. The plugin’s name is .html on PAGES.
This is a simple but helpful plugin. It is easy to use. Just download the plugin, upload it to your plugin directory, activate it. Now enjoy your .html style!