Modify label on view exposed filter
Finally i got the answer . Actually it should be used like YOURMODULE_form_views_exposed_form_alter only . No need of activities_page_1_ as expected . Am adding the answer below : 

/**
 * Implements hook_form_FORM_ID_alter().
 */
function module_name_form_views_exposed_form_alter(&amp;$form, $form_state, $form_id) {
  $form['created']['min']['#title'] = t('From');
  $form['created']['max']['#title'] = t('To');
}