How to create form that will add content in drupal?

Question

I can create form with drupal forms api, but I don't know how to do hook to edit or add the content

Answer 1

In your form_submit handler, you can write the contents of your form variables (such as $form_state) to the database, or send an email, and so on.

See http://drupal.org/node/751826 for details on submitting forms.