diff --git a/src/Concerns/Arrayable.php b/src/Concerns/Arrayable.php
new file mode 100644
index 0000000..b4aef68
--- /dev/null
+++ b/src/Concerns/Arrayable.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Novaday\Moadian\Concerns;
+
+use ReflectionClass;
+use ReflectionProperty;
+
+trait Arrayable
+{
+    public function toArray(): array
+    {
+        $array = [];
+        $reflection = new ReflectionClass($this);
+
+        foreach ($reflection->getProperties(ReflectionProperty::IS_PUBLIC) as $property) {
+            $array[$property->getName()] = $property->isInitialized($this) ? $property->getValue($this) : null;
+        }
+
+        return $array;
+    }
+}
diff --git a/src/Contracts/Arrayable.php b/src/Contracts/Arrayable.php
new file mode 100644
index 0000000..602e67f
--- /dev/null
+++ b/src/Contracts/Arrayable.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace Novaday\Moadian\Contracts;
+
+/**
+ * @template TKey of array-key
+ * @template TValue
+ */
+interface Arrayable
+{
+    /**
+     * Get the instance as an array.
+     *
+     * @return array<TKey, TValue>
+     */
+    public function toArray(): array;
+}
diff --git a/src/InvoiceHeader.php b/src/InvoiceHeader.php
index a99ee07..b013786 100644
--- a/src/InvoiceHeader.php
+++ b/src/InvoiceHeader.php
@@ -3,10 +3,13 @@
 namespace Novaday\Moadian;
 
 use DateTime;
+use Novaday\Moadian\Contracts\Arrayable;
 use Novaday\Moadian\Services\VerhoeffService;
 
-class InvoiceHeader
+class InvoiceHeader implements Arrayable
 {
+    use Concerns\Arrayable;
+
     protected const CHARACTER_TO_NUMBER_CODING = [
         'A' => 65, 'B' => 66, 'C' => 67, 'D' => 68, 'E' => 69, 'F' => 70, 'G' => 71, 'H' => 72, 'I' => 73,
         'J' => 74, 'K' => 75, 'L' => 76, 'M' => 77, 'N' => 78, 'O' => 79, 'P' => 80, 'Q' => 81, 'R' => 82,
@@ -16,7 +19,17 @@ class InvoiceHeader
     /**
      * MOADIAN_USERNAME
      */
-    public string $clientId;
+    protected string $clientId;
+
+    public function getClientId(): string
+    {
+        return $this->clientId;
+    }
+
+    public function setClientId(string $clientId): void
+    {
+        $this->clientId = $clientId;
+    }
 
     /**
      * unique tax ID (should be set by setTaxID )
@@ -118,16 +131,6 @@ class InvoiceHeader
      */
     public ?string $crn;
 
-    /**
-     * customs declaration cottage number
-     */
-    public ?string $cdcn;
-
-    /**
-     * customs declaration cottage date
-     */
-    public ?int $cdcd;
-
     /**
      * billing ID
      */
@@ -163,21 +166,6 @@ class InvoiceHeader
      */
     public float $tbill;
 
-    /**
-     * total net weight
-     */
-    public ?float $tonw;
-
-    /**
-     * total Rial value
-     */
-    public ?float $torv;
-
-    /**
-     * total currency value
-     */
-    public ?float $tocv;
-
     /**
      * settlement type
      */
@@ -203,17 +191,59 @@ class InvoiceHeader
      */
     public ?float $tax17;
 
-    public function __construct(string $username = null)
-    {
-        $this->clientId = $username;
-    }
+    /**
+     * customs declaration cottage number
+     */
+    public ?string $cdcn;
 
-    public function toArray(): array
-    {
-        $arr = get_object_vars($this);
-        unset($arr['clientId']);
-        return $arr;
-    }
+    /**
+     * customs declaration cottage date
+     */
+    public ?int $cdcd;
+
+    /**
+     * total net weight
+     */
+    public ?float $tonw;
+
+    /**
+     * total Rial value
+     */
+    public ?float $torv;
+
+    /**
+     * total currency value
+     */
+    public ?float $tocv;
+
+    public ?string $tinc;
+
+    public ?string $lno;
+
+    public ?string $lrno;
+
+    public ?string $ocu;
+
+    public ?string $oci;
+
+    public ?string $dco;
+
+    public ?string $dci;
+
+    public ?string $tid;
+
+    public ?string $rid;
+
+    public ?int $lt;
+
+    public ?string $cno;
+
+    public ?string $did;
+
+    public ?array $sg;
+
+    public ?string $asn;
+    public ?int $asd;
 
     public function setTaxID(DateTime $date, int $internalInvoiceId)
     {
diff --git a/src/InvoiceItem.php b/src/InvoiceItem.php
index d56c6ca..6685f27 100644
--- a/src/InvoiceItem.php
+++ b/src/InvoiceItem.php
@@ -2,8 +2,12 @@
 
 namespace Novaday\Moadian;
 
-class InvoiceItem
+use Novaday\Moadian\Contracts\Arrayable;
+
+class InvoiceItem implements Arrayable
 {
+    use Concerns\Arrayable;
+
     /**
      * service stuff ID
      */
@@ -154,8 +158,7 @@ class InvoiceItem
      */
     public float $tsstam;
 
-    public function toArray(): array
-    {
-        return get_object_vars($this);
-    }
+    public ?float $cui;
+    public ?float $cpr;
+    public ?int $sovat;
 }
diff --git a/src/Services/SignatureService.php b/src/Services/SignatureService.php
index 3f68ad9..35f8261 100644
--- a/src/Services/SignatureService.php
+++ b/src/Services/SignatureService.php
@@ -32,20 +32,19 @@ public static function normalizer(array $data, array $headers): string
 
         $normalizedData = [];
 
-        $flatted = self::flattener($data);
+        $flatted = self::dot($data);
 
         ksort($flatted);
 
         foreach ($flatted as $value) {
-
-            if (is_bool($value)) {
-                $value = $value ? 'true' : 'false';
-            }
-
-            if ($value === '' || $value === null) {
+            if (blank($value)) {
                 $value = '#';
             } else {
-                $value = strtr($value, [ '#' => '##']);
+                if (blank($value = strval($value))) {
+                    $value = '#';
+                } else {
+                    $value = str_replace('#', '##', $value);
+                }
             }
 
             $normalizedData[] = $value;
@@ -54,16 +53,18 @@ public static function normalizer(array $data, array $headers): string
         return implode("#", $normalizedData);
     }
 
-    private static function flattener(array $array, string $prefix = ''): array
+    private static function dot(array $array, string $prepend = ''): array
     {
-        $flatted = [];
+        $results = [];
+
         foreach ($array as $key => $value) {
-            if (is_array($value)) {
-                $flatted = array_merge($flatted, self::flattener($value, "$prefix.$key"));
+            if (is_array($value) && !empty($value)) {
+                $results = array_merge($results, self::dot($value, $prepend . $key . '.'));
             } else {
-                $flatted["$prefix.$key"] = $value;
+                $results[$prepend . $key] = $value;
             }
         }
-        return $flatted;
+
+        return $results;
     }
 }