iPhone is slowing down or facing intermittent issues, you might want to try clearing cache to fix it. There is no such thing as a system-level cache cleaner on iOS, so you can’t really clear cache on your iPhone in one shot. What you can do is clear the cache individually from various apps, if they support that feature. To clear the cache on the iPhone, we’ll take a three-pronged approach.
To clear unused apps (but not documents and data stored in those apps), go to Settings > General > iPhone Storage. Now tap Enable next to Offload Unused Apps. To reset system settings such as network, home screen layout, or keyboard dictionary, go to Settings > General > Reset. Now pick the appropriate option to complete the process. You can also quickly upload photos to iCloud and delete the local copies to clear some space from your iPhone. Go to Settings > General > iPhone Storage. Now tap Enable next to Optimise Photos.