Generic ISO
A hybrid live ISO, for hosting providers and hypervisors that take nothing but an uploaded ISO. It boots to a text console, not a desktop, and it boots on legacy BIOS machines as well as UEFI ones.
Get the file from the Download page.
Configuring it
Like the cloud image, it reads a cidata NoCloud seed or a config-2 OpenStack seed if one is attached, and cloud-config(5) describes what goes in one.
It is the same content as the cloud image, in ISO form, so the same applies to logging in.
Installing from it
It carries a text mode version of live-install, so it can perform a full installation as well as run live. The installation guide covers the steps.