It sounds like you're looking for some control over what your child can and can't do on the device. Obviously you can keep a child from downloading apps that you don't approve of by not sharing the Apple ID / App store password, but that only works until the child figures out that they can just create their own Apple ID. I wonder if one of the MDM (Mobile Device Management) solutions might come closer to giving you what you want. There are at least two that I can think of off the top of my head: Jamf Now (
https://www.jamf.com/products/jamf-now/) and Apple Server. Jamf Now is free for the first three devices, and it is probably reasonably easy to set up, so that is what I would suggest first. Apple Server includes something called Profile Manager, which is similar to Jamf Now, but because it is part of a much larger package of services in Server may be quite involved to get running properly. I don't think either of these are going to be able to keep your child from using the apps that come built into iOS (Safari, Mail, etc) but at least you're reasonably guaranteed that the child won't be able to download or use other apps that you might not want them getting into at their present age (say, Facebook, Snapchat, or Instagram).