It’s as follows :

Page 1:config.php
class mymailer
    {
        function mysendmail($from,$to,$subject='sub',$body='msg',$content_type='text/html',$auth=true,$host=MAIL_HOST,$username=MAIL_USERNAME,$password=MAIL_PASSWORD)
        {
            require_once "Mail.php";   //you should install PEAR::Mail module in your server
            $headers = array ('From' => $from,
                'To' => $to,
                'Subject' => $subject,
                'Content-type'=>$content_type
            );
            $smtp = Mail::factory('smtp',
                array ('host' => $host,
                'auth' => $auth,
                'username' => $username,
                'password' => $password)
            );
            $mail = $smtp->send($to, $headers,$body);
            if (PEAR::isError($mail))
            {
                //return $mail->getMessage();
                return 'F';
            }
            else
            {
                return 'S';
            }
        }
    }

You can call this class as :

Page 2: mail_sending_page.php
require_once "config.php";
$from="frommail@company.com";
$to="tomail@example.com";
$subject="My Mail Subject";
$body="This is the body of this mail. Your content goes here.";
$mails=new mymailer;
$mails->mysendmail($from,$to,$subject,$body);