There are a few things which you cannot do on portable Apple devices. One of them is to open zip files: there no stock app or feature that lets you open / extract zip files. And so, if you wish to open zip file on your iPhone/iPad, you’ll have to rely on third-party apps.
Because the audio programs are in zip folders you need a special app designed to unzip the folder on smart phones and portable devices. A consideration is the size of the zip folders. Most of them are hundreds of megabytes therefore, you may want to download and unzip the folder on a computer first and then transfer the files you want on your portable device. If you want to extract zip files directly to a portable device, learn more here: