Drupal 7 hook_fom_alter not working for custom fields I have added custom field for email address in my content type.
I want to assigned default email address to this field. Following is my code.

function request_order_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  if($form_id == 'request_order_node_form') {
    dsm($form);
    $form['field_your_email']['#default_value'] = 'sam@gmail.com';
  }
} 


But I am not getting default value in my field.
Set default value in field setting and try this after that : 

print $form['field_your_email']; //check where default value is

$form['field_your_email']['und'][0]['value']['#default_value'] = 'sam@gmail.com';