Hit the <insert>
key to toggle inserting vs overwriting.
C-h k <insert>
tells you:
<insert>
runs the command overwrite-mode
, which is an interactive
compiled Lisp function in simple.el
.
It is bound to insertchar
, insert
.
(overwrite-mode &optional ARG)
Toggle Overwrite mode.
With a prefix argument ARG
, enable Overwrite mode if ARG
is
positive, and disable it otherwise. If called from Lisp, enable
the mode if ARG
is omitted or nil
.
When Overwrite mode is enabled, printing characters typed in
replace existing text on a one-for-one basis, rather than pushing
it to the right. At the end of a line, such characters extend
the line. Before a tab, such characters insert until the tab is
filled in. M-x quoted-insert
still inserts characters in
overwrite mode; this is supposed to make it easier to insert
characters when necessary.
See the Emacs manual, node Minor Modes.