Submitting new alter field I created a select/dropdown list and it works:
function hook_form_hook_ID_alter(&amp;$form){
  $term_data = array(....) //array of key =&gt; values

  $form['elements']['location']['medical_name'] = array(
    '#type' =&gt; 'select',
    '#title' =&gt; t('Medical Area'),
    '#options' =&gt; $term_data,
    '#empty_option' =&gt; t('-None-'),
  );
}

but when I submit the webform, the field is not submitted. What I mean by submitted, when I go to results of the webform, there does not exist a medical_name field, thus the field is not registered. This is an alter function, so yes I am creating medical_name field on alter. I checked the formState-&gt;getValue and it is there. So I am wondering what may be the problem? I want to add the field programmatically.
This is not the solution I want, it is temporary:
In the UI, I created a select field with key medical_area
then with my alter function, it just override the webform and stored it there.
What I want:
Without having to create a select field in the UI, to be able to create a field through the alter function.