Software > System Software > macOS > Mac OS X Mountain Lion
To get started, you will first need to have
* A high-speed internet connection (ISP fees may apply).
* Sufficient data storage available for the download.
* A blank Flash/Pen/Thumb/USB Drive with at least 8 GB of space.
* A blank Dual-Layer or Double-Sided DVD.
Get Mac OS X Mountain Lion with Apple ID.