$fields = DrupalCoreEntityEntityTypeManagerInterface->getStorage('field_storage_config')->loadMultiple();

foreach ($fields as $key => $instance) {
   $label = $instance->getLabel();
   $name = $instance->getName();
}

$definitions = Drupal::service('entity_field.manager')->getFieldDefinitions('node', 'page');
foreach ($definitions as $definition) {
  $label = $definition->getLabel();
}