This is the official manual for the latest Org-mode release.
When TODO keywords are used as workflow states (see Workflow states), you
might want to keep track of when a state change occurred and maybe take a
note about this change. You can either record just a timestamp, or a
time-stamped note for a change. These records will be inserted after the
headline as an itemized list, newest first1. When taking a lot of notes, you might
want to get the notes out of the way into a drawer (see Drawers).
org-log-into-drawer to get this behavior—the recommended
drawer for this is called
LOGBOOK2. You can also
overrule the setting of this variable for a subtree by setting a
Since it is normally too much to record a note for every state, Org mode expects configuration on a per-keyword basis for this. This is achieved by adding special markers ‘!’ (for a timestamp) or ‘@’ (for a note with timestamp) in parentheses after each keyword. For example, with the setting
(setq org-todo-keywords '((sequence "TODO(t)" "WAIT(w@/!)" "|" "DONE(d!)" "CANCELED(c@)")))
To record a timestamp without a note for TODO keywords configured with ‘@’, just type C-c C-c to enter a blank note when prompted.
you not only define global TODO keywords and fast access keys, but also request that a time is recorded when the entry is set to DONE3, and that a note is recorded when switching to WAIT or CANCELED. The setting for WAIT is even more special: the ‘!’ after the slash means that in addition to the note taken when entering the state, a timestamp should be recorded when leaving the WAIT state, if and only if the target state does not configure logging for entering it. So it has no effect when switching from WAIT to DONE, because DONE is configured to record a timestamp only. But when switching from WAIT back to TODO, the ‘/!’ in the WAIT setting now triggers a timestamp even though TODO has no logging configured.
You can use the exact same syntax for setting logging preferences local to a buffer:
#+TODO: TODO(t) WAIT(w@/!) | DONE(d!) CANCELED(c@)
In order to define logging settings that are local to a subtree or a
single item, define a LOGGING property in this entry. Any non-empty
LOGGING property resets all logging settings to
nil. You may then turn
on logging for this specific tree using STARTUP keywords like
logrepeat, as well as adding state specific
TODO(!). For example
* TODO Log each state with only a time :PROPERTIES: :LOGGING: TODO(!) WAIT(!) DONE(!) CANCELED(!) :END: * TODO Only log when switching to WAIT, and when repeating :PROPERTIES: :LOGGING: WAIT(@) logrepeat :END: * TODO No logging at all :PROPERTIES: :LOGGING: nil :END:
 See the option
 Note that the
LOGBOOK drawer is unfolded when pressing <SPC> in the agenda to
show an entry—use <C-u SPC> to keep it folded here
 It is possible that Org mode will record two timestamps
when you are using both
org-log-done and state change logging.
However, it will never prompt for two notes—if you have configured
both, the state change recording note will take precedence and cancel
the ‘Closing Note’.