RE: Documentation

[Drew Adams]

    How does this come about?

    ,----[ C-h k C-x o ]
    | C-x o runs the command other-window
    | (other-window ARG &optional ALL-FRAMES)
    |    which is an interactive built-in function.
    |
    | Select the ARG'th different window on this frame.
    | All windows on current frame are arranged in a cyclic order.
    | This command selects the window ARG steps away in that order.
    | A negative ARG moves in the opposite order.  If the optional second
    | argument ALL_FRAMES is non-nil, cycle through all frames.
    `----

Are you asking how to document a command, function, or variable? If so, see
the Elisp manual, node "Documentation".