Devices running Android 6.0 or later can be configured with multiple user accounts. These accounts include the owner profile account, user account, and guest account. By default, these devices have an owner profile account. If needed, you can create a new user account or a guest account to share the device with other members.
If your children use any of these devices, their activities are monitored only if Norton Family is installed on the account that they use to login to the device. Moreover, if your children use owner profile account to login to their device, they can easily create a new user account or guest account and switch to these accounts to do their online activities. In this case, Norton Family cannot monitor their activities as it is installed only on the owner profile.
Likewise, when your child's device is upgraded to Android 6.0 or later, you get the owner profile account, and all the installed apps, including Norton Family, will be part of this profile. So, it is required that you install Norton Family on the user account that your child uses to login to the device and you prevent your children from creating new user accounts, including guest account. For more information, read Prevent your child from creating new user accounts on Android 6.0 or later devices.