How should I create a custom form?
This shouldn't work as @Alex said, because you are not using Drupal's Form API. You should implement hook_form($node, &amp;$form_state), to create a form.

Sample code which creates a form with a single text field:

function MODULE_form() {
  $form = array();
  $form['title'] = array(
    '#type' =&gt; 'textfield', 
    '#title' =&gt; t('Field description goes here...'),
    '#required' =&gt; TRUE, 
  );
  return $form;
}