Question

I want to be able to customise the user registration form in Drupal 6

I have found thousands of tutorials that show me how to override the structure in which you can output the form as a whole, but I want to move form elements around etc and I cant quite seem to see the best way to do this

Answer 1

Using hook_form_alter you can do whatever you want with a form.

For example changing the weight can change the position on the page.

If you try:

MYMODULE_form_user_profile_form_alter(&$form, $form_state) {
// do your processing here
var_dump($form);
}

replacing MYMODULE with the name of your module.

You will see the structure of the form, you can change values in there to alter, labels weights descriptions etc.