<h1><?php echo $this->hyperlink($this->setting('installation_title', 'Omeka S'), $this->url('top', ['action' => 'index'])); ?></h1>
<h2><?php echo $this->translate('Search'); ?></h2>

omeka/search/index.phtml

<?php echo $this->partial(
    'common/cross-site-search/fulltext-form.phtml',
    ['action' => $this->url(null, ['action' => 'results'], true)]
); ?>
