To make an Educational App for Kids/Childrens have some unique features is must require to be a part of educational apps, especially for kids friendly are:

They must be free of ads, unuseful links and pop-ups etc
Locked menu settings & other features control by adult
There is required to be an option to mute the sound
Language used must be simple
In first priority as childrens/kids are our primary audience
Only required buttons must be placed to drop complexity