Switching between insert and overwrite mode
With the keyboard, press Insert to toggle between overwrite mode and insert mode. In insert mode, any text after the cursor position moves forward to make room for the text you type; in overwrite mode, text after the cursor position is replaced by the text you type. The current mode is displayed on the Status Bar.
With the mouse, click in the area on the Status Bar that indicates the current mode in order to switch to the other mode.