You can redirect http://www.yourdomain.com to http://yourdomain.com by setting below code into .htaccess file.
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.yourdomain.com [NC] RewriteRule ^(.*)$ http://yourdomain.com/$1 [L,R=301]
// Replace yourdomain.com with your actual domain/website name.
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