<?php $form = ActiveForm::begin(['id' => 'contact-form']); ?>
        <?= $form->field($model, 'email',  [
                'inputOptions' => [ 'placeholder' => 'Ihre E-Mail Adresse', 'class' => 'newsletter-cta-mail' ]
        ])->label(false)->textInput(); ?>
        <?= Html::submitButton('20€ Gutschein sichern', ['class' => 'green newsletter-cta-button', 'name' => 'contact-button', 'value' => 'hallo']) ?>
<?php ActiveForm::end(); ?>

results into:

<form id="contact-form" action="/" method="post" role="form">
<input type="hidden" name="_csrf" value="WFlFWnIwU1Y3HnQKSn06GG46PXcjQRUzNCA9KhRiYCxvFXQ9RHIiPA==">     <div class="form-group field-newsletterform-email required has-error">

<input type="text" id="newsletterform-email" class="newsletter-cta-mail" name="NewsletterForm[email]" placeholder="Ihre E-Mail Adresse">

<p class="help-block help-block-error">Verification Code cannot be blank.</p>
</div>  <button type="submit" class="green newsletter-cta-button" name="contact-button" value="hallo">20€ Gutschein sichern</button></form>

But I dont need the wrapping

How to disable this?