The Android OS is the most popular one when it comes to mobile devices. A tablet that runs on Android can have access to a lot more content, games, apps and educational material than others, much of it available for free.
The Dragon Touch K8 Kids is an Android tablet, running 6.0 Marshmallow out of the box at the time of writing. It is a full Android tablet, although the parental controls mean that children cannot access all the features.