change to new apple id on mini-ipad device

I want one of my teenage children to use one of my mini-ipad devices but first would like to remove my apple id from that device and register a new apple id for her under her gmail address. The mini-ipad is running iOS 11.2. I've tried removing the device from my managed devices and also signed out of iTunes & App store on the mini-ipad but it just keeps asking me to sign back in under my account. I don't see any option to register a new apple account. Please help.