Example *with* this property:

```php
<?php 
$inputGroup =  '<div class="input-group"><span class="input-group-addon">@</span>{input}</div>';

// Default layout
$form = ActiveForm::begin();
$form->field(\$model, 'demo', [
        'inputTemplate' => $inputGroup,
]);

// Horizontal layout
$form = ActiveForm::begin(['layout' => 'horizontal']);
$form->field(\$model, 'demo', [
        'inputTemplate' => $inputGroup,
]);
```

Example *without* this property:

```php
<?php 
$inputGroup =  '<div class="input-group"><span class="input-group-addon">@</span>{input}</div>';

// Default layout
$form = ActiveForm::begin();
$form->field(\$model, 'demo', [
        'template' => "{label}\n$inputGroup\n{hint}\n{error}"
]);

// Horizontal layout
$form = ActiveForm::begin(['layout' => 'horizontal']);
$form->field(\$model, 'demo', [
        'template' => "{label}\n{beginWrapper}\n$inputGroup\n{error}\n{endWrapper}\n{hint}"
]);
```

As you see in the second example, without the `inputTemplate` you have to modify the field `template` if you want to change the layout.