In WordPress, Custom Fields is a feature that allows users to add additional information to posts and pages. This information can be any type of metadata, such as dates, links, text, or other data types, to enhance the richness and functionality of content. A common use case for Custom Fields is to add specific information to blog posts, such as a book's ISBN number, the start time of an event, or the price of a product. By using Custom Fields, you can easily display this information in theme templates without modifying the main content. For example, if I am building a book review feature for a blog, I can use Custom Fields to store additional information about books, such as the author, publication date, and ISBN. In this way, in the theme template files of WordPress, I can use the following code to display this information: ```php
ID, 'author', true ) ) : ?><p>Author: <?php echo get_post_meta( $post->ID, 'author', true ); ?></p>