<form method="get" action="<?php echo esc_url(home_url('/')); ?>">
    <div class="form-group">
        <input type="search" name="search" value="" required placeholder="<?php esc_html_e('What you are searching for?', 'univarsal')?>">
        <button type="submit" class="theme-btn thm-btn"><?php esc_html_e('Search', 'univarsal');?></button>
    </div>
</form>