Custom fields are a powerful WordPress feature that allows you to add extra information to your posts, pages, or custom post types. Think of them as additional data containers that store specific details not included in the standard editor.

They work as key-value pairs:

• Key: The name or label of the information (e.g., "Author_Bio").
• Value: The actual content (e.g., "John is an experienced web developer...").

Common uses for custom fields include:

• Displaying book details (ISBN, publisher)
• Adding product specifications
• Showing event dates and locations
• Creating custom post templates

To use custom fields effectively:

1. Enable them in the Screen Options (top right of edit screen).
2. Add your custom field with a unique name.
3. Use code or plugins to display the data on your site.

While powerful, custom fields require careful organization and sometimes coding knowledge. For beginners, plugins like Advanced Custom Fields provide user-friendly interfaces. Remember to back up your site before making significant changes.