To install:

Adobe Creative Suite CS6 Master Collection is a comprehensive suite of creative applications, including Photoshop, Illustrator, InDesign, Premiere Pro, and more.

You cannot buy it from the official website. However, if you previously purchased a retail box (with a serial number), you can download the official DMG from Adobe’s legacy download servers (via the "Other Downloads" section of your Adobe account).

The Adobe Creative Suite 6 Master Collection DMG is not the best creative suite anymore. It lacks modern codecs, 3D features, and collaboration tools. But it remains one of the most interesting pieces of software ever released. In a world where you rent your toothbrush and subscribe to your car’s heated seats, a 12GB disk image from 2012 has become a radical object. It whispers: You could own this. You still can.