Unfortunately, CCleaner can't be used on iOS devices, such as the Apple Watch, iPhone, and iPad, because of the sandboxing requirement that was introduced by Apple.
What is Apple's sandboxing? How does it impact CCleaner?
Sandboxing requires that an app can only have access to its own files and some user files. As CCleaner needs to clean data from the system and other applications, it cannot work on iOS and iPadOS because of this requirement.
Please note: There are some apps on the iOS App Store which claim to be CCleaner Free and CCleaner Professional. We can confirm that these are NOT our products, and we are working with Apple to have them removed.
If you or someone you know has purchased this app, you are eligible for a refund from the app store and you can find out how to do this here.