The Apple Human Interface Guidelines (HIG) is a set of standards that Apple Inc. has developed to provide a consistent look and feel across all of their products. The guidelines provide design principles, recommendations, and resources for designing user interfaces for Apple products.
The HIG covers a wide range of topics, from the basics of user interface design to best practices for creating a great user experience. For example, the guidelines recommend using a consistent visual language across all Apple products, such as using the same typefaces and colors. They also provide advice on how to create effective navigation and how to create intuitive interactions. Additionally, the guidelines provide information on accessibility features and how to design for a wide range of users.