Here are a few options for a post tag description for “iPASS功能” in Traditional Chinese, varying in length and focus:

**Option 1 (Short & Concise):**

> 關於 iPASS (一卡通) 的功能介紹和相關資訊。
>
> *Translation: Information and introductions about the functions of iPASS (EasyCard).*

**Option 2 (Slightly More Detailed):**

> 涵蓋 iPASS (一卡通) 的各項功能，包括支付、乘車、儲值等等。 探索如何善用 iPASS 在日常生活中的便利性。
>
> *Translation: Covers various functions of iPASS (EasyCard), including payment, transportation, top-up, and more. Discover how to make the most of iPASS’s convenience in daily life.*

**Option 3 (Emphasis on Benefits):**

> 了解更多關於 iPASS (一卡通) 的功能，掌握這張智慧卡的優點。 從快速支付到便捷乘車，發掘 iPASS 如何提升您的生活效率。
>
> *Translation: Learn more about the functions of iPASS (EasyCard) and understand the advantages of this smart card. Discover how iPASS improves your life efficiency, from quick payments to convenient transportation.*

**Option 4 (Focus on Technical aspects, if applicable):**

> 技術深入分析 iPASS (一卡通) 運作原理及功能。包含 NFC 技術應用、資料加密、整合應用等。
>
> *Translation: In-depth technical analysis of the iPASS (EasyCard) operating principles and functions. Includes applications of NFC technology, data encryption, and integrated applications.*

**Which option to choose depends on the content related to the tag.**

* If the posts are simple “how-to” guides, option 1 or 2 might suffice.
* If the blog explores the benefits and usages, option 3 is suitable.
* if the blog has more technical details about iPASS, optiion 4 can work.

Regardless of your choice, remember to also apply appropriate keywords to optimize the tag for search engines! Keywords would be “iPASS”, “一卡通”, “功能”, “支付”, “交通”, “乘車”, “儲值” etc.