Document NavigationTabType

development/components/form/types-reference/navigation-tab-type.md

@@ -13,3 +13,54 @@ This form type is used as a container of sub forms, each sub form will be render
 
 | Option       | Type   | Default value                     | Description                                                                               |
 | :----------- | :----- | :-------------------------------- | :---------------------------------------------------------------------------------------- |
+
+## Usage and description
+
+This form type [was introduced in {{< minver v="8.1.0">}}](https://github.com/PrestaShop/PrestaShop/pull/28752) in the product form. 
+
+The new Product page uses this form type as the base form type. 
+
+Its example usage has been documented in an example module: [`demoproductform`](https://github.com/PrestaShop/example-modules/tree/master/demoproductform).
+
+The module hooks to `actionProductFormBuilderModifier` to modify the `FormBuilder` for the Product page. 
+The `ProductFormModifier` adds a new `CustomTabType` (created by the module) to the `FormBuilder` (which is a `NavigationTabType`).
+
+```php
+$this->formBuilderModifier->addAfter(
+    $productFormBuilder,
+    'pricing',
+    'custom_tab',
+    CustomTabType::class,
+    [
+        'data' => [
+            'custom_price' => $customProduct->custom_price,
+        ],
+    ]
+);
+```
+
+This `CustomTabType` contains a simple form type: 
+
+```php
+public function buildForm(FormBuilderInterface $builder, array $options)
+{
+    parent::buildForm($builder, $options);
+    $builder
+        ->add('custom_price', MoneyType::class, [
+            'label' => $this->trans('My custom price', 'Modules.Demoproductform.Admin'),
+            'label_tag_name' => 'h3',
+            'currency' => $this->defaultCurrency->iso_code,
+            'required' => false,
+            'constraints' => [
+                new NotBlank(),
+                new Type(['type' => 'float']),
+                new PositiveOrZero(),
+            ],
+        ])
+    ;
+}
+```
+
+It is rendered this way in the BO Product page: 
+
+{{< figure src="../img/navigation-tab-type.png" title="NavigationTabType" >}}