What are some best practices for handling email functionalities in PHP, considering potential server differences like qmail and sendmail?

When working with email functionalities in PHP, it's important to consider potential server differences like qmail and sendmail. To ensure compatibility across different servers, it's recommended to use the built-in PHP `mail()` function which abstracts the underlying mail system. This function allows you to send emails without worrying about the specific server configuration.

$to = "recipient@example.com";
$subject = "Test Email";
$message = "This is a test email.";
$headers = "From: sender@example.com";

// Send email using the built-in mail() function
$mail_sent = mail($to, $subject, $message, $headers);

if ($mail_sent) {
    echo "Email sent successfully.";
} else {
    echo "Email sending failed.";
}