<div class="row">
<a class="btn btn-info btn-rounded pull-right" id="add-more-btn" title="Adicionar mais arquivos">Adicionar</a>
</div>
<div class="row arquivo_upload">
  <div class="col-md-6" >
       <?=   $form->field($model, '[0]descricao')->textInput(['maxlength'   => true]) ?>
   </div>
  <div class="col-md-5">
      <?= $form->field($model, '[0]arquivo_url')->widget(kartikfileFileInput::classname(), [
        'options' => ['multiple' => true],
        'language' => 'pt',
        'pluginOptions' => [
            'showUpload' => false,
            'showPreview' => false,
            'browseLabel' => '',
            'removeLabel' => '',
        ],
    ])->label('Arquivo') ?>
</div>

<div class="row">
<a class="btn btn-info btn-rounded pull-right" id="add-more-btn" title="Adicionar mais arquivos">Adicionar</a>
</div>
<div class="row arquivo_upload">
<div class="col-md-6" >
    <?= $form->field($model, '[0]descricao')->textInput(['maxlength' => true]) ?>
</div>
<!--  FileInput Yii2  -->
<div class="col-md-5">
    <?= $form->field($model, '[0]arquivo_url')->fileInput()->label('Arquivo') ?>
</div>