Unable to clear safari history

Yes- the clear button is greyed out. I just spoke to Apple support and helped resolve the issue. The reason the clear history button is grayed out is due to the fact that I have enabled Screen Time for my kids. Disabling screen time will then allow your kids to clear history. I think it’s a safety measure to allow parents to view sites their children go to and to track activity.

i Have checked and my children’s phone do not have any restrictions except for when downtime is on. Otherwise all setting are unrestricted

Is clear button grayed out?

Have you checked Settings/Screen Time for any restrictions?