Step 1: So once you’ve set up Guided Access, go to your child’s phone, tap the Phone app and triple-click the Home Button. Now it’s in Guided Access mode. You can’t get out of it.
Step 2: Your child can still make phone calls and your child can receive phone calls.
Even when the screen is asleep, the phone is still in Guided Access mode. The one caveat is if your kids power the phone off, they can override Guided Access. But you’ll know because there’s no way for them to turn Guided Access back on without your Guided Access passcode.
Apple here’s another perfect example of where we need better parental controls.