WinZip is a software application used for file compression and decompression. It allows users to reduce the size of files, making them easier to store and share. By compressing files into a single ZIP format, it helps save disk space and speeds up file transfers over the internet. In addition to compression, WinZip offers features like file encryption, which secures sensitive information, and the ability to create self-extracting files. It supports various file formats, making it a versatile tool for managing large amounts of data efficiently.