Move HTML To Wordpress

A client of mine is interested to switch over to wordpress CMS.his site is in can i install wordpress on his site without breaking his existing site?
once he likes it we want to replace html site to CMS under his root folder.

Yes, you can install right on the root. Wordpress uses index.php as it’s default file for the root, but I believe most servers will look for index.html first. To be safe, just install WP and rename the index.php file it creates. Then the current site can still be viewed and you can start the job of setting up WP. I believe you can also create it in a subfolder off the root, then move it into the root when its ready.

WP is a bear to move once installed. The db is littered with URL references that have to be changed - and they’re not that intuitive. It’s best to go with the first point. Make sure the site indexes are index.html, index.htm, index.php - in that order. that way you can develop alongside the site. when it’s ready to go live, just remove the index.html (but make sure the site will redirect to index.php if index.html is requested directly).