phpmailer 安装或者下载方式:

• 1、从 github 上下载:https://github.com/PHPMailer/PHPMailer/
  2、使用 composer 安装:
  composer require phpmailer/phpmailer
  发送之前需要拥有自己的邮件服务器，测试的时候其实用自己申请的免费邮箱最方便了，不需要自己再搭建服务器了，可能要配置邮箱的SMTP服务，大部分公共邮箱（163、qq等）为了安全默认是关闭的。
  3、配置调用
  引用文件：

  use PHPMailer\PHPMailer\PHPMailer;
  use PHPMailer\PHPMailer\Exception;

  使用：
  function sendEmail(){ //sendEmail()里面可带参数
  //判断openssl是否开启
  $openssl_funcs = get_extension_funcs('openssl');
  if(!$openssl_funcs){
  return ['code'=>0 , 'msg'=>'请先开启openssl扩展'];
  }
  $config['email_smtp_server'] = '127.0.0.1'; //服务器地址
  $config['email_smtp_port'] = 25; //端口
  $config['email_smtp_user'] = ''; //邮件发送账号
  $config['email_smtp_password'] = ''; //邮件发送密码
  $config['email_smtp_name'] = ''; //邮件发送名称
  $to = "510435764@qq.com"; //接收邮箱
  $subject = '测试标题'; //邮件标题
  $content = '测试内容'; //邮件内容
  $addAttachment = ''; //附件
  $mail = new PHPMailer;
  $mail->CharSet = 'UTF-8'; //设定邮件编码，默认ISO-8859-1，如果发中文此项必须设置，否则乱码
  $mail->isSMTP();
  $mail->SMTPDebug = 0; //开启错误调试0关闭 1开启
  //Whether to use SMTP authentication
  $mail->SMTPAuth = true;
  //调试输出格式
  $mail->Debugoutput = 'html';
  //smtp服务器
  $mail->Host = $config['email_smtp_server'];
  //端口 - likely to be 25, 465 or 587
  $mail->Port = $config['email_smtp_port'];
  //$mail->SMTPSecure = 'ssl';// 使用安全协议 tls,ssl
  //用户名
  $mail->Username = $config['email_smtp_user'];
  //密码
  $mail->Password = $config['email_smtp_password'];
  //Set who the message is to be sent from
  $mail->setFrom($config['email_smtp_user'],$config['email_smtp_name']);
  //回复地址
  //$mail->addReplyTo('replyto@example.com', 'First Last');
  //接收邮件方
  if(is_array($to)){
  foreach ($to as $v){
  $mail->addAddress($v);
  }
  }else{
  $mail->addAddress($to);
  }
  $mail->isHTML(true);// send as HTML
  //标题
  $mail->Subject = $subject;
  //邮箱正文
  $mail->Body = $content;
  //添加附件
  if (!empty($addAttachment)){
  $mail->addAttachment($addAttachment);
  }
  try {
  //$mail->send();
  if (!$mail->send()) {// 发送邮件
  echo "发送失败: " . $mail->ErrorInfo;// 输出错误信息
  } else {
  echo '发送成功';
  }
  }catch (Exception $e){
  return ['code'=>0 , 'msg'=>$e->getMessage()];
  }

}