Doodly rainbow is a paid add-on. It is not included in the purchase of either the Standard or Enterprise license by default. You can see what's included at both levels here (www.doodly.com/pricing).
Doodly Rainbow is a separate purchase which can be made here (www.doodly.com/rainbow). It allows you to toggle between defaulted black and white images and colored images that are provided in the software. The Rainbow option instantly doubles the number of images that are already provided inside of Doodly. This option is not available for imported images.
If you have existing scenes with Doodly images that you’d like to convert into their Rainbow equivalent, you can do so by clicking Settings in the timeline then, toggle the Doodly Rainbow option to ON. This will apply to all scenes in your project.