Add a word-count column to WordPress Posts List (Dashboard view).

wordpress-wordcount-column.php

<?php

/**
 * Add a word-count column to WordPress Posts List (Dashboard view). 
 *
 * Custom code for adding a new column to the posts list.
 * The new column will contain the number of words in the post
 *
 * @link https://imelgrat.me/wordpress/customize-wordpress-post-management-page/
 */

function post_word_count($post_id)
{
    $content = get_post_field('post_content', $post_id);
    $word_count = str_word_count(strip_tags(strip_shortcodes($content)));
    return $word_count;
}
add_filter('manage_posts_columns', 'wordcount_column');

function wordcount_column($columns)
{
    $columns['wordcount'] = 'Word count';
    return $columns;
}
add_action('manage_posts_custom_column', 'show_wordcount');

function show_wordcount($name)
{
    global $post;
    switch ($name) {
        case 'wordcount':
            $wordcount = post_word_count($post->ID);
            echo $wordcount;
    }
}