I have 2 ipads, and cannot see my documents on the second one

I have 2 ipads: I am not able to see the documents I've written on icloud on the second one. I've checked my settings for icloud and the app itself ont he second ipad, but nothing seems to work. From the app itself - on my settings page - I switched the " use icloud" botton to "on", but it doesn't stay on. Whenever I leave the settings page ad come back, it automatically switches back to "off", as if I didn't have the option...

Please help!