What Is WinZip?

When transferring files from computer to computer via cable, disk or Internet, it is often necessary to "compress" files to make them smaller so they can be sent more quickly.
The files are not damaged or changed, just stored in a different way. A good analogy is to think of it like taking a large letter, folding it up and putting it inside a small envelope. You send the envelope which now takes up less space, but at the other end the envelope can be opened and the large letter folded out again.
This is the advantage of using compressed files. You take a large file or group of files, compress and place in one small compressed file, then send. At the other end the contents can be "extracted" back to their original size and used as normal.
WinZip is the most well-known of many programs able to compress files, in this case to what are known as Zip files with the filename extension .zip