7z is a file compression format created by the software 7-Zip. It is known for its high compression ratio, which means it can reduce the size of files significantly compared to other formats like ZIP or RAR. The 7z format supports various compression algorithms, allowing users to choose the best method for their needs. 7-Zip is an open-source program that can create and extract 7z files, as well as handle many other formats. It is available for multiple operating systems, including Windows, Linux, and macOS. The software is popular for its efficiency and user-friendly interface, making file management easier for everyone.