PHP form to multiple recipients - php

Question

I found and copied this code for sending an email via a form fill and it works, but I don't know anything about PHP coding.
I thought that I could add multiple addresses like ... $email_to: = "email1#email.com, email2#email.com, email3#email.com"; ... but this only sends to the last one in the list.
I know it seem simple to you guys, but I am not able to decipher the other posts about this subject, since the other code samples are not exactly like mine, and I know nothing about how the code works.
if(isset($_POST['email'])) {
// EDIT THE 2 LINES BELOW AS REQUIRED
$email_to = "email1#email.com, email2#email.com, email3#email.com";
$email_subject = "Someone registered on website.com";
function died($error) {
// your error code can go here
echo "We are very sorry, but there were error(s) found with the form you submitted. ";
echo "These errors appear below.<br /><br />";
echo $error."<br /><br />";
echo "Please go back and fix these errors.<br /><br />";
die();
}
// validation expected data exists
if(!isset($_POST['first_name']) ||
!isset($_POST['last_name']) ||
!isset($_POST['email']) ||
!isset($_POST['cell_phone']) ||
!isset($_POST['text_me'])){
died('We are sorry, but there appears to be a problem with the form you submitted.');
}
$first_name = $_POST['first_name']; // required
$last_name = $_POST['last_name']; // required
$email_from = $_POST['email']; // required
$cell_phone = $_POST['cell_phone']; // required
$text_me = $_POST['text_me']; // required
$error_message = "";
$email_exp = '/^[A-Za-z0-9._%-]+#[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';
if(!preg_match($email_exp,$email_from)) {
$error_message .= 'The Email Address you entered does not appear to be valid.<br />';
}
$string_exp = "/^[A-Za-z .'-]+$/";
if(!preg_match($string_exp,$first_name)) {
$error_message .= 'The First Name you entered does not appear to be valid.<br />';
}
if(!preg_match($string_exp,$last_name)) {
$error_message .= 'The Last Name you entered does not appear to be valid.<br />';
}
if(strlen($cell_phone) < 2) {
$error_message .= 'Please enter your cell phone number.<br />';
}
if(strlen($text_me) < 2) {
$error_message .= 'Please choose whether we can text you or not.<br />';
}
if(strlen($error_message) > 0) {
died($error_message);
}
$email_message = "Form details below.\n\n";
function clean_string($string) {
$bad = array("content-type","bcc:","to:","cc:","href");
return str_replace($bad,"",$string);
}
$email_message .= "First Name: ".clean_string($first_name)."\n";
$email_message .= "Last Name: ".clean_string($last_name)."\n";
$email_message .= "Email: ".clean_string($email_from)."\n";
$email_message .= "Cell Phone: ".clean_string($cell_phone)."\n";
$email_message .= "Text Me?: ".clean_string($text_me)."\n";
// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
#mail($email_to, $email_subject, $email_message, $headers);
?>```
... Please tell me what I can do to make it send to multiple emails.
Thanks in advance!
Dan