How to include PDF in Wordpress Searches

example_usage.php

<?php

if (have_posts()) {
    while (have_posts()) {
        the_post();

        if (get_post_mime_type() == 'application/pdf') {
            // Customize how you display PDF files
            echo '<a href="' . esc_url(get_permalink()) . '">' . esc_html(get_the_title()) . '</a>';
        } else {
            // Regular display for posts and pages
            // ...
        }
    }
}

include_pdf_in_search.php

<?php

function include_pdf_in_search($query) {
    if ($query->is_search && !is_admin()) {
        $post_types = $query->get('post_type');
        if (empty($post_types)) {
            $post_types = ['post', 'page'];
        }
        if (!is_array($post_types)) {
            $post_types = [$post_types];
        }
        if (!in_array('attachment', $post_types)) {
            $post_types[] = 'attachment';
        }
        $query->set('post_type', $post_types);
        $query->set('post_status', ['publish', 'inherit']);
        $query->set('post_mime_type', 'application/pdf');
    }
    return $query;
}
add_action('pre_get_posts', 'include_pdf_in_search');