PHP contact form going to page with code

Question

I want my contact form to send an email to my email. I coded the form but have never coded PHP before. I tried writing it. However, when I submit the form it goes to a webpage with the PHP code instead of the success or failure message. This is the HTML code for the form.

<form method="post" action="send_form_email.php">
    <label for="name">Name</label>
    <input type="text" id="name" name="name" placeholder="FirstName LastName">

    <label for="phone">Phone Number</label>
    <input type="tel" id="number" name="number" placeholder="(555) 555-5555">

    <label for="email">Email</label>
      <input type="email" id="email" name="email" placeholder="youremail@email.com">

    <label for="message">Message</label>
    <textarea id="message" name="message" placeholder="Tell us about your project." style="height:100px"></textarea>

    <input type="submit" value="Submit">
  </form>

    <form method="post" action="send_form_email.php">
    <label for="name">Name</label>
    <input type="text" id="name" name="name" placeholder="FirstName LastName">

    <label for="phone">Phone Number</label>
    <input type="tel" id="number" name="number" placeholder="(555) 555-5555">

    <label for="email">Email</label>
      <input type="email" id="email" name="email" placeholder="youremail@email.com">

    <label for="message">Message</label>
    <textarea id="message" name="message" placeholder="Tell us about your project." style="height:100px"></textarea>

    <input type="submit" value="Submit">
  </form>

This is the PHP code. I took from a library and tried to tailor it to the form I already had.

<?php
if(isset($_POST['email'])) {

    // EDIT THE 2 LINES BELOW AS REQUIRED
    $email_to = "myemail@domain.com";
    $email_subject = "Testing Contact Form";

    function died($error) {
        //error message
        echo "There were error(s) with your submission ";
        echo "These errors appear below.<br /><br />";
        echo $error."<br /><br />";
        echo "Please go back and fix these errors.<br /><br />";
        die();
    }


    // validation expected data exists
    if(!isset($_POST['name']) ||
        !isset($_POST['number']) ||
        !isset($_POST['email']) ||
        !isset($_POST['message'])) {
        died('There appears to be a problem with your submission. Please try again.');       
    }



    $name = $_POST['name']; // required
    $number = $_POST['number']; // required
    $email_from = $_POST['email']; // required
    $message = $_POST['message']; // required

    $error_message = "";
    $email_exp = '/^[A-Za-z0-9._%-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';

  if(!preg_match($email_exp,$email_from)) {
    $error_message .= 'The Email Address you entered does not appear to be valid.<br />';
  }

    $string_exp = "/^[A-Za-z .'-]+$/";

  if(!preg_match($string_exp,$name)) {
    $error_message .= 'The name you entered does not appear to be valid.<br />';
  }


  if(strlen($message) < 2) {
    $error_message .= 'The message you entered do not appear to be valid.<br />';
  }

  if(strlen($error_message) > 0) {
    died($error_message);
  }

    $email_message = "Form details below.\n\n";


    function clean_string($string) {
      $bad = array("content-type","bcc:","to:","cc:","href");
      return str_replace($bad,"",$string);
    }



    $email_message .= "Name: ".clean_string($name)."\n";
    $email_message .= "Email: ".clean_string($email_from)."\n";
    $email_message .= "Phone Number: ".clean_string($number)."\n";
    $email_message .= "Message: ".clean_string($message)."\n";

// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
@mail($email_to, $email_subject, $email_message, $headers);  
?>

<!-- include your own success html here -->

Thank you for contacting us. We are excited to work with you. We will be in touch as soon as possible!

<?php

}
?>