如何在wordpress中添加.html extn end of all page / post url

We developed a html static site to WordPress (CMS) blog site ...

For SEO, Static url for best SE cache/crawl...
Best way to On crawling and indexing sites for the Google index..

Dynamic URLs vs. static URLs details ref doordie.co.in/seo/160216

So, how add .html extension end of all page/post url in wordpress without plugins

For eg. chennaitechnologies.com/google-adwords/

To: chennaitechnologies.com/google-adwords.html

Any code or .htaccess possible?

For posts

Try the following as perma-link structure:

%category%/%postname%.html

For pages

There is a free plugin for that called .html on PAGES plugin

You can do this by editing permalinks of your WordPress Blog/site. In wp-admin, look for settings and click in permalinks. Select the custom option and put the .html at the end.