Forced using www or non www

If you want to forced redirect all visitor from www to non-www, you can try using below mod_rewrite method inside your .htaccess file:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.domain\.com$ [NC]
RewriteRule ^(.*)$ http://domain.com/$1 [R=301,L]

And for using www :

RewriteEngine On
RewriteCond %{HTTP_HOST} !^www.domain.com$ [NC]
RewriteRule ^(.*)$ http://www.domain.com/$1 [R=301,L]

ok that all for today :) Enjoy