Some SEO checks can flag a website for duplicate content if you can visit this using both www and non-www versions, to resolve this you can setup a .htaccess file with one of the two following commands.
The first command will force any visitors to the website to use www.yourdomain.com:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^example.com [NC]
RewriteRule ^(.*)$
http://www.example.com/$1 [L,R=301,NC]
Whilst this command will force visitors to use yourdomain.com:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.example\.com [NC]
RewriteRule ^(.*)$
http://example.com/$1 [L,R=301]
Just replace example.com with your domain name.
