It depends on which cache you’re referring to. Here’s a list of all iPhone caches and where to find them:
Browser cache – Safari browser caches can be found in the Settings app > Safari. Google Chrome’s caches can be found in the History section of the settings menu (3 dots) within the app itself.
Browser cookies – Just like browser caches, it depends on the browser. For Safari, it’s found in the Settings app > Safari. For Google Chrome, it’s found in the Settings app > Chrome (this only disables third-party cookies, but not Goole Chrome’s own cookies).
App cache – You can find app caches by opening each individual app in the first Settings menu.