The Command key is a modifier key found on Apple keyboards, typically labeled with the ⌘ symbol. It is used to perform various shortcuts and commands in macOS and other Apple software. For example, pressing the Command key along with the letter "C" allows users to copy selected text or items, while Command + V pastes them. This key is similar to the Control key found on Windows keyboards, which serves a similar purpose for shortcuts in the Windows operating system. The Command key enhances productivity by enabling quick access to functions without navigating through menus, making it an essential tool for users of Apple computers.