Home page: using custom fields for posts and pages

You’re not being very specific so it’s hard to give you any help. But if you would like to output both pages and posts in the same loop you need to customize your query so that it includes both posts and pages. Learn about http://codex.wordpress.org/Class_Reference/WP_Query.

Or if you want the posts to be outputted at one place and the pages in another place, http://codex.wordpress.org/Function_Reference/get_pages or maybe http://codex.wordpress.org/Function_Reference/wp_list_pages.

Update

To mix posts and pages in one loop you need to query both post types. Try adding query_posts like this:

<?php query_posts('post_type=post,page'); ?>
<?php while (have_posts()) : the_post(); ?>

    <?php if ( get_post_meta($post->ID, 'highlights', true)) { ?>

        <?php the_title() . "<br>"; ?>

    <?php } ?>

<?php endwhile; ?>