How to remove .html, .php, etc (extension) from URL?

To remove the .html extension from your urls, you can use the following code in root/htaccess :

RewriteEngine on

RewriteCond %{THE_REQUEST} /([^.]+)\.html [NC]
RewriteRule ^ /%1 [NC,L,R]
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule ^ %{REQUEST_URI}.html [NC,L]

NOTE: If you want to remove any other extension, for example to remove the .php extension, just replace the html everywhere with php in the code above.