The instructions on the download page provide guidance on which version is likely to be most suitable.

Please use the correct version for your processor. You will find versions for Intel based Macs and for older PPC based Macs.

Several versions of the complete install package are available. These packages allow Moodle to be installed, along with the prerequisites that includes a web server, database and scripting language (Apache, MySQL and PHP in this case). If you want to use Moodle on an OS X Server connected to the internet please read the instructions Step by step installation on a OS X Server. Moodle4Mac does not have sufficient security for public, production servers - only use for private, local testing purposes. You will find other downloads for Linux and Window Operating Systems that may involve more customization of configuration files. Moodle4Mac is available from Moodle packages for Mac OS X. The complete install packages for Mac OS X are named Moodle4Mac and allow a very easy way to install Moodle on your Mac computer (laptop, desktop, server).