<IfModule mod_rewrite.c>
RewriteEngine On
# match any URL with www and rewrite it to https without the www
RewriteCond %{HTTP_HOST} ^(www.)(.*) [NC]
RewriteRule (.*) http://%2%{REQUEST_URI} [L,R=301]
# Removes .php (change the .php to .html if you don't have any php files)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^.]+)$ $1.php [NC,L]
</IfModule>