We have Family Sharing set up on our iPhones so any apps our two girls want have to be approved by an adult before they can be installed. What would happen if we approve an app that comes with a free trial? Ie, when the first payment is due, would it then automatically take the payment because it has technically been pre-authorised or will it have to ask permission to take the money?

It’ll just take the money cancel the trial as soon as you’ve signed up.

But the way it works is very odd – I read here that you should cancel it on both the adult’s phone and the child’s phone but we can’t access the child account in the way it says (we are unable to click on the child’s Apple ID to access the subscriptions (it is greyed out). I am sure we have set it up correctly as everything else seems to work.