storage

Hello, I have tried and failed to view what is stored on my iCloud. I get lost trying to follow the directions I find on the internet. Can anyone explain to me in simple terms just what I need to do. Thanks in advance.

I think this is an iPad 2 but it's of no consequence to my inquiry. The machine is a good 6 or 7 or more years old. Under Settings>>General>>About it lists Capacity as 12.8GB. But that isn't a power of two, so I presume it's not including a few GBs allotted to iOS and so this is a 16GB machine...

Apologies if this has benn covered before but if so I cannot find it. My storage on the iPad is getting full and this is because two apps save all the data too, which I don't want. The apps are Dropbox and Eyefi Mobi. The only way I can see to delete the data is to delete the app, which I don't...