How do I clear prior website pages from my phone?
How do I clear a prior website pages that are open in my phone?
iPhone 15 Plus, iOS 18
If you just mean the pages themselves and you're using Safari, see:
Open and close tabs in Safari on iPhone - Apple Support
If you mean Safari's history, tap the Bookmarks icon at the bottom of the Safari window, tap the "clock" icon to get to History, and delete as appropriate. Or go to Settings -> Apps -> Safari and scroll down to Clear History and Website Data and you can delete for an entire time period there.
Regards.