How do I prevent mails sent through PHP mail() from going to spam? [duplicate]

You must to add a needle headers:

Sample code :

$headers = "From: [email protected]\r\n";
$headers .= "Reply-To: [email protected]\r\n";
$headers .= "Return-Path: [email protected]\r\n";
$headers .= "CC: [email protected]\r\n";
$headers .= "BCC: [email protected]\r\n";

if ( mail($to,$subject,$message,$headers) ) {
   echo "The email has been sent!";
   } else {
   echo "The email has failed!";
   }
?> 

There is no sure shot trick. You need to explore the reasons why your mails are classified as spam. SpamAssassin hase a page describing Some Tips for Legitimate Senders to Avoid False Positives. See also Coding Horror: So You'd Like to Send Some Email (Through Code)

<?php

$subject = "this is a subject";
$message = "testing a message";




  $headers .= "Reply-To: The Sender <[email protected]>\r\n"; 
  $headers .= "Return-Path: The Sender <[email protected]>\r\n"; 
  $headers .= "From: The Sender <[email protected]>\r\n";  
  $headers .= "Organization: Sender Organization\r\n";
  $headers .= "MIME-Version: 1.0\r\n";
  $headers .= "Content-type: text/plain; charset=iso-8859-1\r\n";
  $headers .= "X-Priority: 3\r\n";
  $headers .= "X-Mailer: PHP". phpversion() ."\r\n" ;



mail("[email protected]", $subject, $message, $headers); 


?> 

Try PHP Mailer library.
Or Send mail through SMTP filter it before sending it.
Also Try to give all details like FROM, return-path.

$fromMail = 'set your from mail';
$boundary = str_replace(" ", "", date('l jS \of F Y h i s A'));
$subjectMail = "New design submitted by " . $userDisplayName;


$contentHtml = '<div>Dear Admin<br /><br />The following design is submitted by '. $userName .'.<br /><br /><a href="'.$sdLink.'"><b>Click here</b></a> to check the design.</div>';
$contentHtml .= '<div><a href="'.$imageUrl.'"><img src="'.$imageUrl.'" width="250" height="95" border="0" alt="my picture"></a></div>';
$contentHtml .= '<div>Name : '.$name.'<br />Description : '. $description .'</div>';

$headersMail = '';
$headersMail .= 'From: ' . $fromMail . "\r\n" . 'Reply-To: ' . $fromMail . "\r\n";
$headersMail .= 'Return-Path: ' . $fromMail . "\r\n";
$headersMail .= 'MIME-Version: 1.0' . "\r\n";
$headersMail .= "Content-Type: multipart/alternative; boundary = \"" . $boundary . "\"\r\n\r\n";
$headersMail .= '--' . $boundary . "\r\n";
$headersMail .= 'Content-Type: text/html; charset=ISO-8859-1' . "\r\n";
$headersMail .= 'Content-Transfer-Encoding: base64' . "\r\n\r\n";
$headersMail .= rtrim(chunk_split(base64_encode($contentHtml)));

try {
    if (mail($toMail, $subjectMail, "", $headersMail)) {
        $status = 'success';
        $msg = 'Mail sent successfully.';
    } else {
        $status = 'failed';
        $msg = 'Unable to send mail.';
    }
} catch(Exception $e) {
    $msg = $e->getMessage();
}

This works fine for me.It includes mail with image and a link and works for all sorts of mail ids. The clue is to use all the header perfectly.

If you are testing it from localhost, then set the below before checking:

How to set mail send from localhost xampp:

1. comment everything in D:/xampp/sendmail/sendmail.ini and mention the below under

   [sendmail]

   smtp_server=smtp.gmail.com smtp_port=587 error_logfile=error.log debug_logfile=debug.log [email protected] auth_password=your-mail-password [email protected]

2. In D:/xampp/php/php.ini a. Under

   [mail function]

   SMTP = smtp.gmail.com smtp_port = 587

b. set sendmail_from = [email protected] c. uncomment sendmail_path = "\"D:\xamp\sendmail\sendmail.exe\" -t" Hence it should be look like below

sendmail_path = "\"D:\xamp\sendmail\sendmail.exe\" -t"

d. comment sendmail_path="D:\xamp\mailtodisk\mailtodisk.exe" Hence it should be look like below

;sendmail_path="D:\xamp\mailtodisk\mailtodisk.exe"

e. mail.add_x_header=Off