functions.php

<?pjp

function banana__query_modifications($query) {

	if ($query->is_main_query() && get_query_var('post_type') == 'faqs') {
		$query->set('posts_per_page', -1);
		$query->set('orderby', 'taxonomy');
		$query->set('order', 'DESC');
	}

	/* if ($query->is_main_query() && $query->is_tax()) {
		$query->set('orderby', 'title');
		$query->set('order', 'ASC');
	} */

}

add_action('pre_get_posts', 'banana__query_modifications');

?>

get_the_terms_example.php

    <ul class="faqs accordion">
    <?php $cat_name = null; while (have_posts()) : the_post(); ?>

        <?php $terms = get_the_terms($post->ID, 'categories');
        if ($terms && !is_wp_error($terms)) : 
            if ($cat_name != $terms[0]->name) :
                $cat_name = $terms[0]->name; ?>
                <h2><?php echo $cat_name; ?></h2>          
         <?php endif; ?>

        <?php endif; ?>

        <li id="faq-<?php the_ID(); ?>">
            <h3><?php the_title(); ?></h3>
            <div class="answer"><?php the_field('answer'); ?></div>
        </li>

        <?php endwhile; ?>
    </ul>