How can I block internet access on my child's phone?

Sometimes I need to completely cut internet access during homework or family time without taking the phone away. What’s the most effective way to block all internet on a child’s Android or iPhone while still allowing calls and certain apps?

For Android, you can use Screen Time in settings to disable Wi-Fi and data on a schedule. For iPhones, use Screen Time to turn off Safari and specific apps. I find a monitoring app like mSpy gives more control, letting me block internet instantly from my own phone.