If you have wordpress website you just need to make few settings to make
your wordpress site SMPT authenticated enabled.

There is a WordPress plugin named WP Mail SMTP which allows you to send all
WordPress emails via SMTP instead of using default wp_mail() function. You
also can specify an SMTP Username and Password to force authenticate before
sending emails. You can download it from below url:

 http://downloads.wordpress.org/plugin/wp-mail-smtp.0.9.1.zip

1. Download
2. Upload to your /wp-contents/plugins/ directory.
3. Activate the plugin through the ‘Plugins’ menu in WordPress.

You should go to its Advanced Email Options page by clicking on Email link
in Settings box to specify below configurations:
* From Email – which email address that emails should be sent from,
leave blank to keep the default
* From Name – which name that emails should be sent from, leave blank to
keep the default
* Make sure ‘Send all WordPress emails via SMTP.‘ option is selected
* SMTP Host – : mail.yourdomain.com
* SMTP Port –: 25
* If you need to use SMTP Authentication, let check on ‘Yes: Use SMTP
authentication.‘ option then provide an SMTP Username and Password
* Click Save Changes button to make them affected.