You can force the device to stop caching files by connecting it to a computer with a cable and enabling Safari developer mode.
- Enable Web Inspector on the mobile device:
Settings > Safari > Advanced > Web Inspector
- Enable Dev tools in Safari on macOS:
Safari > Preferences > Advanced tab > Show Develop in menu bar
- Connect the device to the computer
- Open the dev tools panel for the device from Safari on the computer:
Develop > Example's iPhone > example.com/page
- To disable caching, go to the Network tab and make sure the little icon for "no cache" is blue (looks like a cylinder with a crossout through it).
- Now you should be able to just hit refresh anytime on the iOS device and you will get an up to date non-cached version!
If you're a web developer this is the ideal way to do it because now you have access to the extremely useful full dev tools panel. And you don't have to keep repeating an annoying process if you need to get a fresh version all the time, not just clear the cache once.
If you're just a general user trying to clear their cache, you might want to use one of the other methods here.
Update: You can now connect to the device over WiFi. May still require initial setup with the cable, but you can definitely connect without it after that.
Develop > Example's iPhone > Connect Via Network