Open the Settings app
Tap Safari
Tap Clear History and Website Data
Tap Clear History and Data to confirm
To delete only website data, go to Settings
Tap Safari
Tap Advanced
Tap Website Data
Tap Remove All Website Data
For Chrome, open the Chrome app
Tap the three dots
Tap History
Tap Clear Browsing Data
Select the data you want to delete
Tap Clear Browsing Data
For Firefox, open the Firefox app
Tap the menu button
Tap Settings
Tap Data Management
Select Browsing History
Tap Clear Private Data