How to get token of parent entity in paragraph?
There's nothing out of the box (see this issue for the details). Implementing your own token isn't too tricky.

I haven't had a chance to test this but I'm pretty sure it'll work:

function MODULE_token_info_alter(&amp;$info) {
  $info['tokens']['paragraph']['parent_entity'] = [
    'name' =&gt; 'Parent entity',
    'description' =&gt; 'Parent entity of the paragraph',
  ];
}

function MODULE_tokens($type, $tokens, array $data, array $options, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata) {
  $replacements = [];

  if ($type == 'paragraph' &amp;&amp; $paragraph = $data['paragraph']) {
    $parent = $paragraph-&gt;getParentEntity();
    $bubbleable_metadata-&gt;addCacheableDependency($parent);

    foreach ($tokens as $name =&gt; $original) {
      if ($name == 'parent_entity') {
        $replacements[$original] = $parent-&gt;label();
      }
    }

    $token_service = \Drupal::token();
    if ($parent_entity_tokens = $token_service-&gt;findWithPrefix($tokens, 'parent_entity')) {
      $replacements += $token_service-&gt;generate($parent-&gt;getEntityTypeId(), $parent_entity_tokens, [$parent-&gt;getEntityTypeId() =&gt; $parent], $options, $bubbleable_metadata);
    }
  }

  return $replacements;
}