Ctrl and a key are just "codes" put into software by Microsoft. Here are the only codes I know but they are very helpful in time.
Undoing last performed action
ctrl+s is used to save the document.
It depends on where you are retrieving it from, but if the document is on your computer, go to "My documents" and select the document you want.
control+z = undo
The Undo is done by pressing Ctrl - Z.
It inserts a manual page break.
yes it does
Ctrl Z on a keyboard undoes what you typed before.
It is used to bring you to the start of the document.
Undo is Ctrl-Z. Redo is either Ctrl-Y or in some programs Ctrl-Alt-Z.
ctrl + Z Ctrl +Z is undo for everything
Ctrl + U will underline text that is selected. Ctrl and the plus sign will superscript text. You need to hold the shift key while doing that, otherwise it subscripts the text.