By Default There are 12 tables in WordPress. They are listed below along with their functioning :

1. wp_users: Stores user information, including usernames, passwords (hashed), and email addresses.
2. wp_usermeta: Contains additional metadata associated with users, such as profile information and preferences.
3. wp_posts: Stores the main content of posts, pages, and custom post types, including titles, content, and other related data.
4. wp_comments: Stores comments made on posts, pages, and other content items.
5. wp_commentmeta: Contains metadata associated with comments, such as author details and comment timestamps.
6. wp_terms: Stores the taxonomy terms used to categorize posts, such as categories and tags.
7. wp_term_taxonomy: Defines the taxonomies and their relationships with terms.
8. wp_term_relationships: Associates terms with posts or other content types.
9. wp_termmeta: Stores additional metadata for terms.
10. wp_options: Contains various site-wide settings and configurations.
11. wp_links: Used to manage the blogroll or list of external links (deprecated in newer versions).
12. wp_postmeta: Stores additional metadata for posts, such as custom fields, featured images, and other related information.