Apostle provides a nifty facility for sending app-generated, transactional emails from your application including Wordpress-like mail formatting and full tracking (delivery, opening, clicking etc.) of all emails sent. No need to set up email facilities on your app server!
In Yii community we have lots of extention can send emails, such as YiiMailer and Swift and so on, or even IMAPI, thanks for team contribution.
However, sometimes, in the intranet enviroment, the program cannot run successfully since SMTP /IMAP port been banded. So you need to seek other ways. The most simple way is **call outlook** as COM.