Computer software is a collection of programs and data that instructs a computer on how to perform specific tasks. It can be categorized into two main types: system software, which includes operating systems like Windows and macOS, and application software, which consists of programs designed for end-users, such as Microsoft Word and Adobe Photoshop. Software is essential for the functionality of computers and devices, enabling users to perform various activities, from browsing the internet to creating documents. It operates through code written in programming languages, allowing developers to create applications that meet different needs and enhance user experience.