When I wiped something off the screen of,my I pad the 'predicted text' above the keyboard disappeared .i don't know how to get it back . Can someone advise a techno idiot?
The predictive text goes away if you continue typing, so maybe try to re-type the word and see if the prediction returns--or type another word to see if you get a different prediction. You can also dismiss predictions by tapping on them (at least, on my iPhone you can, maybe iPads are different), and the more often you dismiss a certain prediction, the more you teach the algorithm to never suggest it.
For more information about using predictive text, google your iOS and "predictive text" or "QuickType". There are resources on myriad Apple blogs and Apple itself.