php - want to render back to page after submiting form and form shoub be clear

one text

i have this contact form and php file to submit form, but in this, when i submit form it displays script alert msg about success and failure but i need to go back where form fields are still filled with info. instead of this i want that form should show alert on same page and form field shoud be cleared. how to do it? i am very beginner in php. dont know where to update code and how.

    <?php

    if (isset($_POST['name']) && isset($_POST['email']) && isset($_POST['tel']) && isset($_POST['loc']) && isset($_POST['message'])) {

     $name = $_POST['name'];
     $email = $_POST['email'];
     $tel = $_POST['tel'];
     $loc = $_POST['loc'];
     $message = $_POST['message'];

     if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
      echo "Kindly provide valid Email Address.";
     } else {
      $body = $name . "\n" . $email . "\n" . $tel . "\n" .  $loc . "\n" . $message;

     /* if (mail('services@brickboys.com.au', 'Service Enquiry', $body, 'From:' . $email)) {
     echo (mail('services@brickboys.com.au', 'Service Enquiry', $body, 'From:' . $email))."Thanks for contacting us.";
      }*/ 
      if (mail('services@brickboys.com.au', 'Service Enquiry', $body, 'From:' . $email)) {
        echo "Thanks for contacting us.";
          }
      else {
       echo "<script>alert('Sorry!, there is a problem in sending email. Please call us on +61 452 534 200')</script>";
      }
     }
    } else {
     echo 'Message could not be sent.';
    }



    $curlx = curl_init();

    curl_setopt($curlx, CURLOPT_URL, "https://www.google.com/recaptcha/api/siteverify");
    curl_setopt($curlx, CURLOPT_HEADER, 0);
    curl_setopt($curlx, CURLOPT_RETURNTRANSFER, 1); 
    curl_setopt($curlx, CURLOPT_POST, 1);

    $post_data = 
    [
        'secret' => '6LfRXOEhAAAAAOWyRGugvbPdYOhkztlz1aMcEwKP', //<--- your reCaptcha secret key
        'response' => $_POST['g-recaptcha-response']
    ];

    curl_setopt($curlx, CURLOPT_POSTFIELDS, $post_data);

    $resp = json_decode(curl_exec($curlx));

    curl_close($curlx);

    if ($resp->success) 
    {
        echo "<script>alert('Thanks For connecting us..we will get back to you soon..')</script>";
    } else 
    {
        // failed
        echo "<script>alert('Please verify you are human..')</script>";
        exit;
    }

    ?>

<div class="col-md-6 padding-15">
                    <div class="contact-form">
                        <!-- https://brickboys.com.au/contact.php -->
                        <form action ="https://brickboys.com.au/contact.php"
                        method="post" id="ajax_form" class="form-horizontal">
                            <div class="form-group colum-row row">
                                <div class="col-sm-6">
                                    <input type="text" id="name" name="name" class="form-control" placeholder="Name" required>
                                </div>
                                <div class="col-sm-6">
                                    <input type="email" id="email" name="email" class="form-control" placeholder="Email" required>
                                </div>
                            </div>
                            <div class="form-group colum-row row">
                                <div class="col-sm-6">
                                    <input type="tel" id="tel" name="tel" class="form-control" pattern="[0-9]{10}" placeholder="Phone 0452534200" required>
                                </div>
                                <div class="col-sm-6">
                                    <input type="text" id="loc" name="loc" class="form-control" placeholder="Project Location">
                                </div>
                            </div>
                            <div class="form-group row">
                                <div class="col-md-12">
                                    <textarea id="message" name="message" cols="30" rows="5" class="form-control message" placeholder="Message" required></textarea>
                                </div>
                                <div class="g-recaptcha col-sm-6 mt-2" data-sitekey="6LfRXOEhAAAAAJMek8MJn-kTKIzO-AKfg7JIp3zu"></div>
                            </div>
                            
                            
                            <div class="form-group row">
                                <div class="col-md-12">
                                    <button id="submit" class="default-btn" type="submit">Send Message</button>
                                </div>
                            </div>
                            <div id="form-messages" class="alert" role="alert"></div>
                        </form>
                    </div>
                </div>
            </div>
        </div>
    </section>

<!-- begin snippet: js hide: false console: true babel: false -->

Source