About cst : h form and c form

Hello friends,

I feel thankful to you people for always guiding me.

Now my question is about CST ;

1)

I know what is H form(thanks to you all), but where shall the procedure of this h form would done?

I mean I how should I apply fr this H form and which authority will give me the h form so that I can issue it to my suppliers.?

2)

what is difference between H and C  form?