Setting up a child's first iPhone or iPad
Give them their own account from the start. Sharing yours is what causes the problems later.
What's usually going on
A child signed in to a parent's account sees the parent's messages, photos, and purchases, and can't be given limits of their own. Apple's Family Sharing is designed for this: the child gets their own account, and you approve what it can do.
Worth trying first
Create a child account.
On your own iPhone: Settings, your name, Family, then add a member and choose to create a child account. Use their real birth date, since the protections depend on it.
Turn on Ask to Buy.
With it on, every purchase and download, including free ones, comes to your phone for approval first.
Set Screen Time from your phone.
In Settings, Family, tap the child's name, then Screen Time. Set downtime overnight, limits for app categories, and content restrictions for their age.
Choose a Screen Time passcode they don't know.
It is separate from the device passcode. Without it, the limits can simply be switched off.
Decide on location sharing together.
Find My can show the device's location to the family. It works better as something agreed than something discovered.
When to hand it over
If the child is already using your account and things need untangling, if there are several children and devices, or if the family uses a mix of Apple, Android, and game consoles and you want the rules to match across all of them.
Your own technologist, on call.
Tell us a little about your setup. We'll take it from there.