My php Contact Form on Website isn't Working

Question

My php Contact Form on my website isn't working. The template is from bootstrap. How do i get/build the PHP/AJAX needed for my form to work correctly? What else am i missing? This is my contact.php form. I welcome any feedback! Thanks

    <?php
if(!empty($_POST["send"])) {
    $name = $_POST["Name"];
    $email = $_POST["Email"];
    $subject = $_POST["subject"];
    $content = $_POST["content"];

    $toEmail = "admin@examplewebsite.com";
    $mailHeaders = "From: " . $name . "<". $email .">\r\n";
    if(mail($toEmail, $subject, $content, $mailHeaders)) {
        $message = "Your contact information is received successfully.";
        $type = "success";
    }
}
require_once "contact-view.php";
?>

Here's a copy of my contact.html code

<div class="col-lg-6">
            <form action="forms/contact.php" method="post" role="form" class="php-email-form">
              <div class="form-row">
                <div class="col-md-6 form-group">
                  <input type="text" name="name" class="form-control" id="name" placeholder="Your Name" data-rule="minlen:4" data-msg="Please enter at least 4 chars" />
                  <div class="validate"></div>
                </div>
                <div class="col-md-6 form-group">
                  <input type="email" class="form-control" name="email" id="email" placeholder="Your Email" data-rule="email" data-msg="Please enter a valid email" />
                  <div class="validate"></div>
                </div>
              </div>
              <div class="form-group">
                <input type="text" class="form-control" name="subject" id="subject" placeholder="Subject" data-rule="minlen:4" data-msg="Please enter at least 8 chars of subject" />
                <div class="validate"></div>
              </div>
              <div class="form-group">
                <textarea class="form-control" name="message" rows="5" data-rule="required" data-msg="Please write something for us" placeholder="Message"></textarea>
                <div class="validate"></div>
              </div>
              <div class="mb-3">
                <div class="loading">Loading</div>
                <div class="error-message"></div>
                <div class="sent-message">Your message has been sent. Thank you!</div>
              </div>
              <div class="text-center"><button type="submit">Send Message</button></div>
            </form>
          </div>

Answer 1

if(!empty($_POST["send"])) {

Here you check if an input named send isn't empty.

But your HTML code does not have any input named send.

Simply add <input type="hidden" name="send" value="1"> somewhere inside the <form>.