How do I stop child form bypassing Screen Time on iPhone?

• Do you have a Screen Time Passcode set on the phone?
• Are you managing it from your phone using Family Sharing?

When you set the Screen Time Passcode, you will see that when you go to Settings > General > Date & Time on your child's device, the option to set the time is greyed out and you cannot adjust it manually.

Iphone1980 wrote: Her phone lock 10 pm till 6 am. But it shows time spend on whatsapp in locked hours and first pick up is like 2 am during locked hours. Can the app report wrong info to me?

Remove the phone from her bedroom during those hours. Problem solved.

Did she tell you that she changed the time previously and now claiming something else?

A simple test to determine if Screen Time is showing you the wrong information is to put the phone in your room overnight and see if it still shows Screen Time Activity.

If she knows the lock time and has to look for ways to bypass Screen Time and more importantly to disobey your clear expectations for cell phone use, then you may need to look for a different solution. There are still phones available for less than $40 that do not have any apps and with limited messaging capabilities. I suspect once she realizes there are consequences and the thought of being seen with one of these phones instead of an iPhone, she will be much more receptive to respecting your wishes for cell phone use.