You should use Text mode—rather than Fundamental or Lisp mode—to
edit files of text in a human language. Invoke M-x text-mode to
enter Text mode. In Text mode, <TAB> runs the function
tab-to-tab-stop, which allows you to use arbitrary tab stops set
with M-x edit-tab-stops (see Tab Stops). Features concerned
with comments in programs are turned off unless they are explicitly invoked.
The syntax table is changed so that periods are not considered part of a
word, while apostrophes, backspaces and underlines are.
A similar variant mode is Indented Text mode, intended for editing
text in which most lines are indented. This mode defines <TAB> to
run indent-relative (see Indentation), and makes Auto Fill
indent the lines it creates. As a result, a line made by Auto Filling,
or by <LFD>, is normally indented just like the previous line. Use
M-x indented-text-mode to select this mode.
Entering Text mode or Indented Text mode calls the value of the
variable text-mode-hook with no arguments, if that value exists
and is not nil. This value is also called when modes related to
Text mode are entered; this includes Nroff mode, TeX mode, Outline
mode, and Mail mode. Your hook can look at the value of
major-mode to see which of these modes is actually being entered.
Two modes similar to Text mode are of use for editing text that is to be passed through a text formatter before achieving its final readable form.
Another similar mode is used for editing outlines. It allows you to view the text at various levels of detail. You can view either the outline headings alone or both headings and text; you can also hide some of the headings at lower levels from view to make the high level structure more visible.