We often want to gather a collection of files and folders into a single file which we can easily pass to others. It's much easier to do this than to try to send multiple files and folders.
making a zip on Windows: https://support.microsoft.com/en-us/windows/zip-and-unzip-files-8d28fa72-f2f9-712f-67df-f80cf89fd4e5
making a zip on Mac: https://support.apple.com/en-vn/guide/mac-help/mchlp2528/mac