How to specify the SMTP server in PHPMailer?

I want to know how do I get a SMTP server to use PHPMailer to send automatic emails with my created email (email@mydomain.com).

My webhost doesn't provide one. I brought my domain in OnlyDomains and my webhost is 000Webhost.

<?php
require './PHPMailer-master/PHPMailerAutoload.php';

$mail = new PHPMailer;

$mail->isSMTP();                                      // Set mailer to use SMTP
$mail->Host = '';  // Specify main and backup SMTP servers
$mail->SMTPAuth = true;                               // Enable SMTP authentication
$mail->Username = 'noreply@mydomain.com';                 // SMTP username
$mail->Password = '********';                           // SMTP password
$mail->SMTPSecure = 'tls';                            
$mail->From = 'noreply@mydomain.com';
$mail->FromName = 'Admin';
$mail->addAddress('sdfsdf@hotmail.com');               // Name is optional

$mail->WordWrap = 50;                                 // Set word wrap to 50 characters
$mail->isHTML(true);                                  // Set email format to HTML

$mail->Subject = 'swag';
$mail->Body    = 'This is the HTML message body <b>in bold!</b>';
$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 'Message has been sent';
}
?>

Solution

You should see if your web host allows you to use sendmail (which is often an alias for the real SMTP server such as Postfix) on their system. Chances are they do since it is a standard part of most any Linux/Unix setup. And since you say that your web host is 000WebHost it seems like they do support the use of sendmail:

You can use PHP's mail() function to send mail for your visitors…

But they also seem to offer SMTP in their premium package.

Past that, I would recommend not worrying about SMTP & sticking to sendmail for now. Looking at the documentation for PHPMailer it seems that the library can use sendmail:

The PHP mail() function usually sends via a local mail server, typically fronted by a sendmail binary on Linux, BSD and OS X platforms, however, Windows usually doesn't include a local mail server; PHPMailer's integrated SMTP implementation allows email sending on Windows platforms without a local mail server.

Then looking in the examples/ folder in the PHPMailer repository shows there is a sendmail example:

require '../PHPMailerAutoload.php';

//Create a new PHPMailer instance
$mail = new PHPMailer();

// Set PHPMailer to use the sendmail transport
$mail->isSendmail();

//Set who the message is to be sent from
$mail->setFrom('from@example.com', 'First Last');

//Set an alternative reply-to address
$mail->addReplyTo('replyto@example.com', 'First Last');

//Set who the message is to be sent to
$mail->addAddress('whoto@example.com', 'John Doe');

//Set the subject line
$mail->Subject = 'PHPMailer sendmail test';

//Read an HTML message body from an external file, convert referenced images to embedded,
//convert HTML into a basic plain-text alternative body
$mail->msgHTML(file_get_contents('contents.html'), dirname(__FILE__));

//Replace the plain text body with one created manually
$mail->AltBody = 'This is a plain-text message body';

//Attach an image file
$mail->addAttachment('images/phpmailer_mini.png');

//send the message, check for errors
if (!$mail->send()) {
    echo "Mailer Error: " . $mail->ErrorInfo;
} else {
    echo "Message sent!";
}