How do I find out if a video is actual or if it was modified with a Software?
Chameleons do have some pretty wild colors they can change into, and the process is extremely advanced, requiring physicists and biologists to fully understand how it works; check out this video for how it works. Personal note: Something this advanced doesn't happen by random chance.
Anyway, my personal opinions aside, it appears to me, this video was heavily edited by software to get a bigger wow factor. I've edited photos and videos for the better part of 20 years and there are subtle markers that stand out to me.
The biggest tip-off, is at 2:06 into the video when the Chameleon changes blue. If you look carefully at the body, you will see a slight gray outline around the edge of the entire Chameleon, it is especially noticeable at the top of his back and the around his forward paw gripping the branch -- that is a not so subtle sign that a poorly made mask has been used to select an area for manipulation. Other tipoffs include the vibrancy of the colors and the purple/blue, and the whole body changing the same color, instead of patches changing color.
As for what software can do this, there are many. If it's a still image you can use Affinity photo, Gimp, or Photoshop. For video, the best (and free) is DaVinci Resolve is what I would recommend. It was specifically designed to do this kind of work!
For an example of how the change could have been done in software, check out this video or this one.
How it happens in Chamelons

                
            
How it's done is software