How to hide few default fields for specific user
Hi for this there is many possible way to achieve this you can use 
https://www.drupal.org/project/field_permissions/releases/7.x-1.0-beta2
(The Field Permissions module allows site administrators to set field-level permissions to edit, view and create fields on any entity.)
or by custom module 

 function mymodule_form_alter(&amp;$form, $form_state, $form_id) {

  if ($form_id === 'you_form_id') {

  if (in_array('user_role_type', $user-&gt;roles)){
    //do stuff

     // Use var_dump  to dump the $form array to see the fields. 
     // var_dump ($form);

     unset($form['mail']);
     unset($form['pass']);
    }
  }
}