arg is for the prefix arg.You want this:

(org-insert-heading)
(insert "hello")

John

-----------------------------------
Professor John Kitchin
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu


On Mon, Jun 5, 2017 at 12:55 AM, <f.nikolakopoulos@gmail.com> wrote:

>
> (org-insert-heading "hello") emacs lisp function ignores argument and
> inserts blank heading.
>
> I think is a change of mode to add the argument but which command.
>
>
>