For Org mode to recognize timestamps, they need to be in the specific format. All commands listed below produce timestamps in the correct format.
Prompt for a date and insert a corresponding timestamp. When point is at an existing timestamp in the buffer, the command is used to modify this timestamp instead of inserting a new one. When this command is used twice in succession, a time range is inserted.
When called with a prefix argument, use the alternative format which
contains date and time. The default time can be rounded to
multiples of 5 minutes. See the option
With two prefix arguments, insert an active timestamp with the current time without prompting.
Like C-c ., but insert an inactive timestamp that does not cause an agenda entry.
Normalize timestamp, insert or fix day name if missing or wrong.
Insert a timestamp corresponding to point date in the calendar.
Access the Emacs calendar for the current date. If there is a timestamp in the current line, go to the corresponding date instead.
Access the agenda for the date given by the timestamp or -range at point (see Weekly/daily agenda).
Change date at point by one day. These key bindings conflict with shift-selection and related modes (see Packages that conflict with Org mode).
On the beginning or enclosing bracket of a timestamp, change its type. Within a timestamp, change the item under point. Point can be on a year, month, day, hour or minute. When the timestamp contains a time range like ‘15:30-16:30’, modifying the first time also shifts the second, shifting the time block with constant length. To change the length, modify the second time. Note that if point is in a headline and not at a timestamp, these same keys modify the priority of an item (see Priorities). The key bindings also conflict with shift-selection and related modes (see Packages that conflict with Org mode).
Evaluate a time range by computing the difference between start and end. With a prefix argument, insert result after the time range (in a table: into the following column).