Hide label for input field

Ok, I found the solution.

<?= $form->field($model, 'sample_text')->textArea()->label(false) ?>

Or you can modify template value for particular field and remove {label} part from it. I.e.:

<p><?= $form->field($page, 'image', [
    'template' => '<div class=\"\">{input}</div><div class=\"\">{error}</div>'
])->fileInput() ?></p>