$ci = get_instance();
    $ci->load->library('email');
    $config['protocol'] = "smtp";
    $config['smtp_host'] = "ssl://smtp.gmail.com";
    $config['smtp_port'] = "465";
    $config['smtp_user'] = "test@gmail.com";
    $config['smtp_pass'] = "test";
    $config['charset'] = "utf-8";
    $config['mailtype'] = "html";
    $config['newline'] = "rn";

    $ci->email->initialize($config);

    $ci->email->from('test@test.com', 'Test Email');
    $list = array('test2@gmail.com');
    $ci->email->to($list);
    $this->email->reply_to('my-email@gmail.com', 'Explendid Videos');
    $ci->email->subject('This is an email test');
    $ci->email->message('It is working. Great!');

    $ci->email->attach( '/test/myfile.pdf');
    $ci->email->send();

public function setemail()
{
$email="xyz@gmail.com";
$subject="some text";
$message="some text";
$this->sendEmail($email,$subject,$message);
}
public function sendEmail($email,$subject,$message)
    {

    $config = Array(
      'protocol' => 'smtp',
      'smtp_host' => 'ssl://smtp.googlemail.com',
      'smtp_port' => 465,
      'smtp_user' => 'abc@gmail.com',
      'smtp_pass' => 'passwrd',
      'mailtype' => 'html',
      'charset' => 'iso-8859-1',
      'wordwrap' => TRUE
    );


          $this->load->library('email', $config);
          $this->email->set_newline("rn");
          $this->email->from('abc@gmail.com');
          $this->email->to($email);
          $this->email->subject($subject);
          $this->email->message($message);
            $this->email->attach('C:UsersxyzDesktopimagesabc.png');
          if($this->email->send())
         {
          echo 'Email send.';
         }
         else
        {
         show_error($this->email->print_debugger());
        }

    }

$ci->email->attach('d:/www/website/test/myfile.pdf');

Content-Type: application/pdf; name="test.pdf"<br>
Content-Disposition: attachment;<br>
Content-Transfer-Encoding: base64<br>
JVBERi0xLjYNJeLjz9MNCjQzNyAwIG9iag08PC9MaW5lYXJpemVkIDEvTCA3OTUyMTYvTyA0Mzkv<br>
RSA2ODEwODcvTiA0L1QgNzk0ODA3L0ggWyA1NjQgMjYxXT4+DWVuZG9iag0gICAgICAgICAgICAg<br>

Content-Type: application/pdf; name="test.pdf"<br>
Content-Disposition: attachment;<br>
Content-Transfer-Encoding: base64<br>
<br>
JVBERi0xLjYNJeLjz9MNCjQzNyAwIG9iag08PC9MaW5lYXJpemVkIDEvTCA3OTUyMTYvTyA0Mzkv<br>
RSA2ODEwODcvTiA0L1QgNzk0ODA3L0ggWyA1NjQgMjYxXT4+DWVuZG9iag0gICAgICAgICAgICAg<br>

'content'       => chunk_split(base64_encode($file_content)),<br>

'content'       => "rn" . chunk_split(base64_encode($file_content)),<br>

<?php

  class Email extends CI_Controller
{
    public Function index();
{
  $config = Array(
          'protocol' => 'smtp',
          'smpt_host' => 'ssl://googlemail.com',
          'smtp_port' => 465,
          'smtp_user' => 'example@gmail.com',
          'smtp_pass' => 'yourpass'
           );
 $this->load->library('email', $config);
 $this->email->set_newline("rn");

 $this->email->from('example@gmail.com');
 $this->email->to('example@gmail.com');
 $this->email->subject('This is a test email sending');
 $this->email->message('This is some message, you can type your own');

 if($this->email->send()
{
    echo "Your email has been sent";
}else{
   show_error($this->email->print_debugger());
}

}


 ?>

$this->load->helper('path');
$path = set_realpath('./images/');

$this->email->attach($path . $your_file);