1.下载PHPMailer

https://github.com/PHPMailer/PHPMailer,下载完成加压后，

把下边的两个文件复制进php的根目录：

2.设置邮件服务器

我们以qq邮箱为例，进入qq邮箱中，点击设置，选中账户选项，在账户下设置POP3/IMAP/SMTP/Exchange/CardDAV/CalDAV服务：

这里提示生成授权码，点击生成就行了，需要用手机发短信，之后得到授权码，保存下来。

3.写发邮件函数

我们这里的函数只是为了演示功能，大家可以自定义自己的函数

function sendMail($body) {
        //invoke mail() function to send mail
    // mail($toaddress, $subject, $mailcontent, $fromaddress);
    date_default_timezone_set('Asia/Shanghai');//设定时区东八区
    require_once('class.phpmailer.php');
    include('class.smtp.php');
    $mail = new PHPMailer;

    $mail->SMTPDebug = 2;                               // Enable verbose debug output

    $mail->isSMTP();                                      // Set mailer to use SMTP
    $mail->Host = 'smtp.qq.com';  // Specify main and backup SMTP servers
    $mail->SMTPAuth = true;                               // Enable SMTP authentication
    $mail->Username = '714034323';                 // SMTP username
    $mail->Password = 'budejddmfejdsedj';                           // SMTP password
    $mail->SMTPSecure = 'ssl';                            // Enable TLS encryption, `ssl` also accepted
    $mail->Port = 465;  

    echo $mail->Host;                                  // TCP port to connect to

    $mail->setFrom('714034323@qq.com', 'Mailer');
    // $mail->addAddress('714080794@qq.com', 'Joe User');     // Add a recipient
    $mail->addAddress('714034323@qq.com');               // Name is optional
    $mail->addReplyTo('714034323@qq.com', 'Information');
    // $mail->addCC('714034323@qq.com');
    // $mail->addBCC('714034323@qq.com');

    // $mail->addAttachment('/var/tmp/file.tar.gz');         // Add attachments
    // $mail->addAttachment('/tmp/image.jpg', 'new.jpg');    // Optional name
    $mail->isHTML(false);                                  // Set email format to HTML

    $mail->Subject = 'Here is the subject';
    $mail->Body    = $body;
    $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';

    if(!$mail->send()) {
        echo 'Message could not be sent.';
        echo 'Mailer Error: ' . $mail->ErrorInfo;
    } else {
        echo ucwords('Message has been sent');
    }
}

4.注意事项

$mail->Host = 'smtp.qq.com';  // Specify main and backup SMTP servers
$mail->SMTPAuth = true;                               // Enable SMTP authentication
$mail->Username = '714034323';                 // SMTP username
$mail->Password = 'budejddmfejdsedj';                           // SMTP password
$mail->SMTPSecure = 'ssl';                            // Enable TLS encryption, `ssl` also accepted
$mail->Port = 465;

上边的设置最重要，Host不能写错，qq的邮箱是需要验证的，所有SMTPAuth设为true，Port按照qq的设置就行了。