Member Rara Avis
A Zip file, Joy, is just a way of compressing files (usually multiple ones) so they take less time to send. You need a special program both to zip the files before sending them and to unzip them once you receive them. Unzipping will restore the files to their original size and their original file extension, so they can be used with whatever program created them.
You can download the program here: http://www.pkware.com/