To clear history on an iPhone, the method depends on the browser used: For Safari:

• Go to Settings > Safari.
• Tap "Clear History and Website Data" to delete all browsing history, cookies, and cache.
• Alternatively, open Safari app, tap the Bookmarks icon, then the History tab (clock icon), swipe left on individual sites to delete them or tap Clear to delete by time period (last hour, today, etc.).

For Chrome:

• Open Chrome app.
• Tap the three-dot menu > History > Clear Browsing Data.
• Choose the time range and confirm clearing history.

Additional:

• Siri search history can be deleted via Settings > Siri & Search > Siri & Dictation History > Delete.
• Disable Safari syncing in iCloud to ensure cleared history doesn't reappear.

These steps help protect privacy and improve device performance.