What is a WordPress Child Theme
A WordPress child theme is a WordPress theme that inherits its functionality from another WordPress theme, the parent theme. Child themes are often used when you want to customize or tweak an existing WordPress theme without losing the ability to upgrade that theme. In the past, there was no easy way of updating WordPress themes without losing all the custom styling and changes that you had made. This becomes chaos when all the sudden you find out a widely used script in popular themes has a major exploit, and you need to update your themes ASAP. It becomes a tough choice because on one hand, you would lose all the custom styles if you update. On the other hand, you risk your site getting hacked if you don’t update fast enough.
The core team and the community decided to solve this problem by introducing the concept of parent theme and child theme. A child theme in WordPress would inherit all the functionality, features, and the code of the parent theme without making any changes to the parent theme itself. This allowed users to change the styling of the parent theme and add/modify features without losing the ability to update the parent theme.