As defined by the WordPress Codex, a child theme is a theme that inherits the functionality and styling of another theme, referred to as the parent theme. Child themes provide a way for designers or developers to create new designs that inherit the functionality of a parent theme.
To understand how child themes work in WordPress, you must understand the relationship between parent and child themes.
A parent theme is a complete theme that includes all of the required WordPress template files and assets for the theme to work. All themes (except child themes) are considered parent themes.
- make your modifications manageable and replicable
- keep customisation separate from parent theme functions,
- allow for updating the parent theme without destroying your improvements.
It is highly recommended to use a child theme when using ready-to-go-themes to modify existing themes while still maintaining their design and code. Precoded themes for WordPress are cheap and easy to implement solutions to create a website.
You can read more about child themes on the WordPress developer website.