1. In overwrite mode, the new input word at the cursor position will replace the original word.

2. In the insert mode, the newly entered word is inserted at the cursor position, and the original word moves backward accordingly.

3. In early computer terminals, if you are in overlay mode, the cursor will become a square instead of the usual vertical line. When the mouse clicks on the input box, a flashing cursor will appear. In general, the default cursor position of Windows system inserts characters, and the cursor moves backward, that is, the input has no effect on the characters behind the cursor.

4. However, Insert is embedded, that is, it is inserted and overwritten. Therefore, when the insert key is pressed and then input, the character after the cursor will be eliminated, that is, it will be replaced by the currently input character, and the default insertion will be restored after being pressed again.