PHP send mail to multiple email addresses

Fore readability sake in the code use an array and implode it to a comma separated string:-

$recipients = array(
  "[email protected]",
  // more emails
);
$email_to = implode(',', $recipients); // your email address
$email_subject = "Contact Form Message"; // email subject line
$thankyou = "thankyou.htm"; // thank you page

Your

$email_to = "[email protected], [email protected], [email protected]"

Needs to be a comma delimited list of email adrresses.

mail($email_to, $email_subject, $thankyou);

Just separate them by comma, like $email_to = "[email protected], [email protected], John Doe <[email protected]>".

Following code will do the task....

<?php

$contacts = array(
"[email protected]",
"[email protected]",
//....as many email address as you need
);

foreach($contacts as $contact) {

$to      =  $contact;
$subject = 'the subject';
$message = 'hello';
mail($to, $subject, $message, $headers);

}

?>