Insert key

The Insert key (often abbreviated INS) is a key commonly found on computer keyboards.

It is primarily used to switch between the two text-entering modes on a personal computer (PC) or word processor.

The insert/overtype mode toggling is not global for the computer or even for a single application but rather local to the text input window in which the Insert key was pressed.

On early text-based computing environments and terminals, when the cursor was in overtype mode, it was represented as a block that surrounded the entire letter to be overstruck; when in insert mode, the cursor consisted of the vertical bar that is highly common among modern applications, or a blinking underline under the position where a new character would be inserted.