What is macintosh hd?

Macintosh HD is the default hard drive on Mac computers, typically formatted with the HFS+ file system. It contains the operating system, system files, applications, and user data. Mac users can store files, install software, and access various system utilities on Macintosh HD. With the release of macOS Catalina, Apple introduced the new APFS file system, therefore Macintosh HD is now formatted with APFS on newer Mac systems. Users can also partition Macintosh HD to create separate sections for data storage or to install multiple operating systems.