To redirect all requests to non-www, add the following lines at the beginning of your website’s .htaccess file:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.yourdomain.com [NC]
RewriteRule ^(.*)$ http://yourdomain.com/$1 [L,R=301]
</IfModule>
Replace yourdomain.com with your actual domain name.