PHPMailer Pro, The Next Generation mail transport class.
Full-featured mail transport class. Support for multi-language content and all major encodings. One single file, SMTP built-in. An entirely new email address engine normalizes email addresses and formats to RFC standards. User input of email address in almost any format: strings, arrays, multi-dimension arrays; Simplified setup. Supports HTML amd plain text messages, all types of attachments.
Features
From the author of the world's most popular mail transport class.
Used by many open-source projects: WordPress, Drupal, 1CRM, SugarCRM, Yii, Joomla! and many more
Integrated SMTP support
Single and multiple To, CC, BCC and Reply-to, custom Return-Path
Multi-part and alternative emails for mail clients that do not read HTML email
You can also follow the blog at https://blog.phpmailer.pro/