On my android you can clear app data and without deleting the app, and it was wondering if I could do the same with my ipad, because with this app when I delete it and re-install it my account is still there and I can't delete my account

Game apps will tend do the same thing. If it is an app that requires an account, the only way that I can think of to totally delete the data would be to delete your account in that app if that's possible.

If I delete my Pages app (which I have done on a few occasions) when I reinstall it, the data is missing until I download it again from iCloud. I have deleted other apps and lost all of the data in those apps, but with some apps it doesn't work and from what I can determine, it occurs in apps that have "accounts" like game apps.

Bear in mind, I am merely guessing at this and I admit that, but that's the way that it seems to work in my experience.