What is the usage of the EXT and OVR mode while entering text in word?

The EXT (Insert) and OVR (Overwrite) modes in Word processing applications like Microsoft Word determine how text is entered and replaces existing text. In EXT mode, new text is added without deleting the existing text, pushing it to the right. In OVR mode, any new text typed replaces the existing text at the cursor's position, effectively overwriting it. Users can toggle between these modes using the "Insert" key on their keyboard.