Which Package and which Format?

It is recommended to install TYPO3 via the PHP package manager composer. See Install TYPO3 via composer. If you are not able to use composer for your project, download the source package from https://typo3.org/download/.

Which File Format to use

The TYPO3 Source package is available as a .zip or .tar.gz distribution. Their content is the same and you should download the one that you will be able to extract directly on your web server (Windows based systems are more likely to use the .zip file while Linux distributions tend to use the .tar.gz file.