I find it almost impossible to do a cut and paste because the onscreen keyboard does not have a Cntrl Key so there is no way to do a Cntrl - V or Cntrl C.
Select the text with your preferred appendage or tool, then you should see a copy bubble pop up, tap that and then you'll see a clipboard icon at the top of your keyboard. Voila
The copy bubble is right above your selected text.
Then to paste, the paste bubble shows up in the predictive text area of the keyboard when you have copied something, but sometimes you have to slide it into view from the left.