Stripe Custom Field

I have a problem with Stripe. Everything works fine when I write in Cardnumber, CVC etc.

But I need to add a custom field so it can work when I write $_POST['ImeiNum'] in charge.php.

Here's my code for the HTML and JQUERY (index.html)

<script type="text/javascript">
        // this identifies your website in the createToken call below
        Stripe.setPublishableKey('pk_test_d34534');


        function processStripeResponse(status, response){
          var form = $('#payment-form<?php echo $row['product_id']; ?>');

          if(response.error){
            form.find('.errors').text(response.error.message);
            form.find('button').prop('disabled', false);
          }else{
            var token = response.id;
            form.append($('<input type="hidden" name="stripeToken" />').val(token));
            form.get(0).submit();
          }
        };

        $(function(){
          $('#payment-form<?php echo $row['product_id']; ?>').submit(function(event) {
            var form = $(this);
            form.find('button').prop('disabled', true);

            Stripe.card.createToken(form, processStripeResponse);

            return false;
          });
         });
    </script>


    <form action="charge.php" method="POST" id="payment-form<?php echo $row['product_id']; ?>">


         <input type="hidden" name="ImeiNum" value="0987654321"> 


          <div>
            <label for="card-number">Card Number</label>
            <input type="text" size="20" data-stripe="number" id="card-number" name="card-number">
          </div>

          <div>
            <label for="cvc">Security Code</label>
            <input type="text" size="4" data-stripe="cvc" id="cvc" name="cvc">
          </div>

          <div>
            <label>Expiration (MM/YYYY)</label>
            <input type="text" data-stripe="exp-month" name="exp-month">
            <span> / </span>
            <input type="text" data-stripe="exp-year" name="exp-year"/>
          </div>

          <input type="submit" name="pay" value="Pay">

       <div class="errors"></div>

    </form>

And here is my code for PHP (charge.php)

<?php
require_once('/storage/content/88/200388/vendor/autoload.php');

    \Stripe\Stripe::setApiKey('pk_test_APId34534');

    $token = $_POST['stripeToken'];

    $IMEI = $_POST['ImeiNum'];

    try {
        $charge = \Stripe\Charge::create(array(
          "amount" => 1000,
          "currency" => "usd",
          "source" => $token,
          "description" => $email),
          "metadata" => array("IMEI" => $IMEI)
        );

        print_r($charge);
    }catch(\Stripe\Error\Card $e){
        echo $e->getMessage();
    }


?>

How do I send a custom field to charge.php?