i’m absolutly new with blender and i do not know how to undo or reverse failed moves or changes like with the back & forth button in word, excel or many other famous programs. 
can anyone give me a hint please?
If you are talking about undo, which most programs have, you can use the Universal Undo Hotkeys.
Use CONTROL+Z to undo. And CONTROL+SHIFT+Z to redo. ALT+U brings up the undo history.
From edit mode, you can use U to undo and SHIFT+U to redo if you like.