How to Clear Your Browser's Cache on an iPhone
We're going to start by clearing out the cache in Safari. Note that this will log you out of any websites you've signed into.
1. Open the Settings app, and scroll down to the fifth group of options (with Passwords & Accounts at the top). Tap Safari at the bottom of this group.
2. Scroll down again and tap 'Clear History and Website Data'.
3. Tap 'Clear History and Data'.