Insert key

The insert key among other keys

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:

• overtype mode, in which the cursor, when typing, overwrites any text that is present in the current location; and
• insert mode, where the cursor inserts a character at its current position, forcing all characters past it one position further.

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.

Overtype mode can also be referred to as over script mode, and is sometimes erroneously referred to as overstrike mode, which is a typography term.

Notably, on some recent keyboards, the Insert key is completely absent (except on the numeric keypad), its space instead filled with a double-size Delete key.^[1]

When keymapping using Octal code, set the desired key by sending \e\161 to perform the "insert" function.

Application usage

Modern word processing applications operate in insert mode by default, but can still be switched to overtype mode by pressing the Insert key. However, the cursor generally does not change into the letter-surrounding box seen on old text-based systems. Instead, an "OVR" indicator on the status bar is highlighted. This is difficult to notice, so other text editors retain the original cursor change in addition to the indicator.

The Insert key, when pressed along with Control or Shift, can also be used to copy or paste in Microsoft Windows. This behavior comes from the Common User Access standard.

Screen readers use the insert key for hotkeys for reading text, speaking formatting information, or opening the screen reader's configuration menu or window.

References

IBM PC keyboard (Windows, US layout)
Esc		F1	F2	F3	F4		F5	F6	F7	F8		F9	F10	F11	F12		PrtScn/ SysRq	Scroll Lock	Pause/ Break
																	Insert	Home	PgUp		Num Lock	∕	∗	−
																	Delete	End	PgDn		7	8	9	+
																					4	5	6
																		↑			1	2	3	Enter
																	←	↓	→		0    Ins		.  Del