M-q (‘fill-paragraph-or-region’) indents the current paragraph or region based on the first line of the paragraph. It will also wrap lines.

Another way is to use `C-x TAB´ to indent the region. This indents the region by one column. Use a numeric prefix argument to change this. Example: `C-u 5 C-x TAB´ to indent by 5. Remember that C-u by itself is used as multiplication by 4 – thus `C-u C-x TAB´ will indent by 4, and `C-u C-u C-x TAB´ will indent by 16.

You can “outdent” the region as well by using a negative prefix: `C-u - 3 C-x TAB´ outdents by 3.

Generally, indenting in text-mode happens via ‘indent-relative’. This function indents up to the indentation of the previous line, then up to the next word in the previous line, and if none is found, according to TabStopList. It is very intuitive, once you get rid of the idea that TAB should insert a tab character. :)

Another way to indent is with ‘open-rectangle’, and unindent with ‘kill-rectangle’, usually bound to ‘C-x r o’ and ‘C-x r k’ respectively.

To use this method, mark the region of text you wish to indent or outdent, then move the point to the left or right the number of horizontal spaces you want to insert or delete. Then type ‘C-x r o’ or ‘C-x r k’.

Useful mnemonics: ‘r o’ = region open, ‘r k’ = region kill

Finally, here’s some simple elisp for really easy indenting. This code lets you just select a region and interactively move it left or right. Add the following to your ~/.emacs file:

;; Shift the selected region right if distance is postive, left if
;; negative

(defun shift-region (distance)
  (let ((mark (mark)))
      (indent-rigidly (region-beginning) (region-end) distance)
      (push-mark mark t t)
      ;; Tell the command loop not to deactivate the mark
      ;; for transient mark mode
      (setq deactivate-mark nil))))

(defun shift-right ()
  (shift-region 1))

(defun shift-left ()
  (shift-region -1))

;; Bind (shift-right) and (shift-left) function to your favorite keys. I use
;; the following so that Ctrl-Shift-Right Arrow moves selected text one 
;; column to the right, Ctrl-Shift-Left Arrow moves selected text one
;; column to the left:

(global-set-key [C-S-right] 'shift-right)
(global-set-key [C-S-left] 'shift-left)