Ctrl + Z is the key or button that you will use if you accidentally erase a line while typing a paragraph.
Ctrl + Z is used for undo in many computer programs. It deletes the last change done to a document and it returns the document to its former state. This key allows user to work without being scared of making mistakes because mistakes can easily be undone. Ctrl + Z is located in the same line with Ctrl + X, C and V and it is very easy to press.