how to add one form element into another form? I have a webform. And I want to add some fields of user registration form to the webform because I also want to add the facility of registration on webform submission. So I want to add those fields of user registration form which are required to the webform.

Any help?
Probably you should do it programatically.

Use hook_form_alter to modify form A, load data of form B by drupal_retrieve_form inside this function and get fields from form B data which you want to add them to form A