frontend/views/basket/cart.php

<?php
    use yii\helpers\Url;
    use yii\web\View;
    
    /**
     * @var View  $this
     * @var float $sum
     * @var int   $count
     */
?>
<a href="<?=Url::to(['/order'])?>" class="basket_btn">
    <p class="price_"><?=$sum?> грн</p>
    <div>
        <span>
            <?=$count?>
        </span>
    </div>
</a>