This code will let you check that the PHP sendmail() function is working on either an Apache or cPanel server.

Here’s the code involved:

<?php  
//*********************************************************************************  
//***** EMAIL TEST SCRIPT TO CHECK THE FUNCTIONALITY OF PHP'S MAIL() FUNCTION *****  
//*********************************************************************************  

/**
 * @name        MailTest
 * @package     testscripts.localdev 
 * @version     0.3.3
 * @since       25-Jun-2021
 * @author      Chris Appleton
 * @abstract    Test PHP's mail() function is working
 */

 
// PHP Mail() FUNCTION TESTING

// THIS SCRIPT TESTS THAT PHP'S SENDMAIL() FUNCTION IS WORKING ON THE SERVER
// CHANGE THE RECIPIENT ADDRESS TO YOUR OWN (MOSTLY SO YOU DON'T SPAM ME!) BEFORE USING - YOU SHOULD NOT NEED TO CHANGE ANYTHING ELSE. 

//THE SCRIPT WILL IDENTIFY THE SERVER, TIME/DATE AND PROVIDE CORRECT HEADER INFORMATION FOR ANALYSIS IF NEEDED. 



//***** RECIPIENT DETAILS *********************************************************  
$to       = "email@example.com";  
$cc       = "";  
$bcc      = "";  
//***** NO NEED TO EDIT BELOW THIS LINE *******************************************  
//***** VARS FOR DEBUGGING ********************************************************  
$host     = getenv('HTTP_HOST');  
$domain   = getenv('HTTP_HOST');  
$version = phpversion();
$date       = date("Y-m-d H:i:s");
//***** BUILD SUBJECT AND MESSAGE FOR TEST MAIL ***********************************  
$subject  = "Testing messages sent from scripts";  
$message .= "This is a test message to check that PHP's mail() function is working correctly.\n";
$message .= "If you have received this, then your server is set up to send mail and is working as intended\n\n";
$message .= "Please do not reply to this email\n\n";  
$message .= "Domain: $domain\n";  
$message .= "PHP version in use: $version\n\n";
$message .= "This message was sent at: $date\n\n";
//***** ADDITIONAL HEADERS FOR COMPLETENESS ***************************************  
$headers  = "From: $domain\r\n";  
if($cc != "")  $headers .= "Cc: $cc\r\n";  
if($bcc != "") $headers .= "Bcc: $bcc\r\n";  
$headers .= "Reply-To: noreply@$domain\r\n";  
$headers .= "X-Mailer: PHP/" . phpversion();  
//***** SEND THE MAIL AND REPORT ANY ERRORS ***************************************  
if(mail($to, $subject, $message, $headers)) echo "Mail sent successfully from $host";  
else echo "Error sending message from $host";  
?>

Copy this code, – making sure that you change the $to variable to an email address of your own, save it inside a file named mailtest.php, for example and then upload this to the default web folder of your webserver.

Visiting domain.com/mailtest.php will trigger the script.