How can HTML knowledge impact the successful implementation of a PHP contact form with customized email recipients?

Having HTML knowledge can impact the successful implementation of a PHP contact form with customized email recipients by allowing you to properly structure the form fields and inputs in the HTML code. This ensures that the form data is sent correctly to the PHP script for processing. Additionally, HTML knowledge can help in styling the form to make it user-friendly and visually appealing.

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $recipient = "customemail@example.com"; // Set custom email recipient
    $subject = "Contact Form Submission";
    $sender = $_POST["email"];
    $message = $_POST["message"];
    
    $headers = "From: $sender\r\n";
    
    if (mail($recipient, $subject, $message, $headers)) {
        echo "Your message has been sent successfully.";
    } else {
        echo "Sorry, there was an error sending your message.";
    }
}
?>

<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
    Email: <input type="email" name="email"><br>
    Message: <textarea name="message"></textarea><br>
    <input type="submit" value="Submit">
</form>