One approach I have found very useful when managing my children's Apple devices is Apple's Family Sharing. As they say "prevention is better than cure ( an ounce of prevention is worth a pound of cure)" certainly applies here. I get to decide whether my child will be allowed to install Apps from the Apple App Store before he/she is exposed to it.
Decide which Apps your child can install
Assuming all the parents have iPhones/iPads/Mac, the parents of the family are both prompted for every purchase the child makes. With the Ask to Buy feature the child will be prompted to ask permission for any purchases they wish to make.
At an appropriate age, as decided by you, the need to ask for permission can be removed. Once this is removed your credit card will be charged directly with any purchases you child makes. Hence you would want to ensure you discuss this with your child and ensure they are at an appropriate stage in their life to be trusted with this feature being tunred off.
Allows kids under 13 to have an account
You children can also have their own AppleID. This makes for a much cleaner setup and you no longer need to worry about your own AppleID being installed on your child's devices. Try to keep to the same recommended approach with computers as with mobile devices, use a separate user profile and password to install on their devices where possible. You can manage the password until they are at an age where they can manage it themselves. More information can be found here Family Sharing and Apple ID for your child.
Find out where your kids are
I think is fantastic to have for the kids, why wouldn't you want to know where you child is? You can use the Find My Friends or the Messages app to keep track of them. And don't worry, you can turn off sharing location in iCloud settings for the parents.
1. Start a Family group
The link https://support.apple.com/en-au/ht201088 will guide you on how to set up family sharing so I won't repeat the steps here. You will need to nominate one person to be the organizer.
2. Add Family members
The link https://support.apple.com/en-au/ht201088 will guide you on how to add family members. This is the simplest way if your children don't already have an Apple ID and as long as you are ok with the child's Apple ID being created with an email address ending in @icloud.com. You can optionally create an email account with your favourite email provider (e.g. Gmail).
Steps for existing Apple ID or separate to @iCloud.com
1. Create an email account (Optional)
Create the email account via your chosen email service provider e.g. www.gmail.com
2. Create an AppleID
Browse to https://appleid.apple.com
Click the link "Create your Apple ID"
Date of birth = <for now enter your birthday as the page will not allow you to enter the actual age of your child "You cannot create an Apple ID because you do not meet the minimum age.....". Don't worry we will fix this later.
3. Add the child to your Family
This step must be done by the Family Organizer:
Add the family member as per the instructions except select the option to provide an email address and enter the childs email address
An email will be sent to the child's email address
Accept the invitation from the child's device
This will being you to the iCloud settings, enter the AppleID and password for the child
Once logged in browse to Settings > iCloud > Invitations
Add a photo
4. Update your child's date of birth for his/hers Apple ID
Login to https://appleid.apple.com as your child's newly create Apple ID
Under the Account section click the "Edit" button
Update the date of birth from your dob to your childs real dob
You will be prompted with the message "Parental consent is required to make this change....will convert this Apple ID into a children's account"
An email will be sent to the Family organizer, Approve the request