Are there any specific PHP commands or functions that are essential for implementing email functionality in a web application?

To implement email functionality in a web application using PHP, you can use the built-in `mail()` function. This function allows you to send emails from your web server using PHP code. You need to provide the recipient's email address, the subject of the email, the message content, and optional additional headers.

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

mail($to, $subject, $message, $headers);