How to clear ios app data?

Question

iOS

Hello. There are long-installed applications on the iPhone, for example, mail.ru, CDEK, etc. They store saved mail from which I have not used for a long time, or delivery tracks that have been received for a long time. I tried to reinstall them, data on mails and tracks still remain and are not deleted in any way. There is no link to the account, the iCloud storage is also empty, in the application settings I did not find the opportunity to clear the data.
So the question is how to remove all this using standard ios tools? Like how on android on each application you can choose to delete data or clear the cache?

Answer 1

Settings -> General -> Storage -> [Desired program] -> Uninstall a program
Try like this, it says that all associated data is deleted with the application.