Как получить value?

<code>
        <?php
            $Shop_IDP = "00011812"; 
            $Order_IDP = "Тест";
            Subtotal_P = "12";
            
            $Password = "pXiNcOFDcmzQRstsk3RgdaHpuM0bcus5RqpMT8tK0ANloa4W175zny7URDo4tudxZtMSJUC8nuLX4p5M";
            $Customer_IDP = "";
            $Card_IDP = "";
            $Lifetime = "300";
            $IData = "";
            $PT_Code = "";
            $MeanType = "";
            $EMoneyType = "";
            $strfiscal = array (
                "customer" => array (
                        "phone" => "+7123123123",
                        "email" => "test@test.ru",
                        "id" => "23412342134"
                    ),
                "taxmode" => 2,
                "lines" => array(  
                        0 => array
                            (
                                "name" => "TEST",
                                "price" => $Subtotal_P ,
                                "qty" => 1,
                                "sum" => $Subtotal_P ,
                                "vat" => -1,
                                "payattr" => 1,
                                "lineattr" => 4
                            ),
                     ),
                "payments" => array(
                        0 => array
                            (
                                "kind" => 1,
                                "type" => 0,
                                "amount" => $Subtotal_P 
                            ),
                    ),
                "total" => $Subtotal_P 
            );

            $Receipt = base64_encode(json_encode($strfiscal));
            $strfiscal_decode = base64_decode($Receipt);


            $Signature = strtoupper(md5(md5($Shop_IDP) . "&" . md5($Order_IDP) . "&" . md5($Subtotal_P) . "&" . md5($MeanType) . "&" . md5($EMoneyType) . "&" . md5($Lifetime) . "&" . md5($Customer_IDP) . "&" . md5($Card_IDP) . "&" . md5($IData) . "&" . md5($PT_Code) . "&" . md5($Password)));

            $ReceiptSignature = strtoupper(hash('sha256', hash('sha256', $Shop_IDP) . "&" . hash('sha256', $Order_IDP) . "&" . hash('sha256', $Subtotal_P) . "&" . hash('sha256', $Receipt) . "&" . hash('sha256', $Password)));

            ?>

            <FORM ACTION="https://fpay.uniteller.ru/v2/pay/" METHOD="GET" target="_blank">
             <input TYPE="hidden" NAME="Shop_IDP" VALUE="<?=$Shop_IDP;?>">
             <input TYPE="hidden" NAME="Lifetime" VALUE="<?=$Lifetime;?>">
             <input TYPE="hidden" NAME="Signature" VALUE="<?=$Signature;?>">
             <input TYPE="hidden" NAME="Receipt" VALUE="<?=$Receipt;?>">
             <input TYPE="hidden" NAME="ReceiptSignature" VALUE="<?=$ReceiptSignature;?>">
             <input TYPE="hidden" NAME="URL_RETURN_OK" VALUE="http://a0332491.xsph.ru/pay_ok/">
             <input TYPE="hidden" NAME="URL_RETURN_NO" VALUE="http://a0332491.xsph.ru/pay_fail/">
             <input TYPE="text" class="form_pay"  NAME="Order_IDP" placeholder="Номер заказа" VALUE="<?=$Order_IDP;?>">

             <!---->
             <input TYPE="text" class="form_pay" NAME="Subtotal_P" id="Subtotal_P"  placeholder="Сумма платежа" VALUE="<?=$Subtotal_P;?>">


            <input TYPE="submit" class="form_pay-btn" NAME="Submit" VALUE="Оплатить">



            </FORM>


</code>