mustain.php

 <?=  $form->field($model, 'tgl_lahir')->widget(DatePicker::classname(), [
                    'language' => 'id',
                    'options' => ['placeholder' => 'Pilih Tanggal Lahir'],
                    'pluginOptions' => [
                        'autoclose' => true,
                        'format' => 'yyyy-mm-dd',
                    ]
                ]);
    ?>