Sitemap.php

<?php /* Template Name: Sitemap */

get_header();
?>

	<div id="primary" class="content-area col-lg-8 offset-lg-2 pt-5">
		<main id="main" class="site-main">
<h1>HTML Sitemap</h1>
<h2 id="pages">Pages</h2>
<ul>
<?php
// Add pages you'd like to exclude in the exclude here
wp_list_pages(
  array(
    'exclude' => '',
    'title_li' => '',
  )
);
?>
</ul>

<h2 id="posts">Posts</h2>
<ul>
<?php
// Add categories you'd like to exclude in the exclude here
$cats = get_categories('exclude=');
foreach ($cats as $cat) {
  echo "<li><h3>".$cat->cat_name."</h3>";
  echo "<ul>";
  query_posts('posts_per_page=-1&cat='.$cat->cat_ID);
  while(have_posts()) {
    the_post();
    $category = get_the_category();
    // Only display a post link once, even if it's in multiple categories
    if ($category[0]->cat_ID == $cat->cat_ID) {
      echo '<li><a href="'.get_permalink().'">'.get_the_title().'</a></li>';
    }
  }
  echo "</ul>";
  echo "</li>";
}
?>
</ul>

<h2>Categories</h2>
<ul><?php wp_list_cats('sort_column=name&optioncount=1&hierarchical=0&feed=RSS'); ?></ul>

		</main><!-- #main -->
	</div><!-- #primary -->

<?php
get_footer();