Here are a few options for the WordPress post_tag description, catering to different needs and audiences, all using Traditional Chinese:

**Option 1: Short & Sweet (Best for general use)**

* **Description:** 包含關於信件格式、撰寫標準、以及範例的標籤。 (Contains tags related to letter formats, writing standards, and examples.)

**Option 2: Slightly More Informative (Helpful for users seeking details)**

* **Description:** 探索書信的格式規範，包括稱謂、正文、結尾等各個部分的寫作細節。也涵蓋不同類型信件的範例，例如求職信、感謝信等等。 (Explore the format regulations of letters, including the salutations, body, closing, and other writing details. It also covers examples of different types of letters, such as job application letters, thank you letters, etc.)

**Option 3: Focus on Practical Application (Good for tutorials/guides)**

* **Description:** 此標籤收錄有關如何正確撰寫不同類型信件的指南。從信封地址到信件內容，教您掌握書信的格式，寫出清晰、專業的信件。 (This tag contains guides on how to correctly write different types of letters. From the envelope address to the content of the letter, it teaches you to master letter formats and write clear, professional letters.)

**Why these are good choices:**

* **Relevant:** They accurately reflect the meaning of the tag “信件格式” (Letter Format).
* **Traditional Chinese:** All descriptions are written in Traditional Chinese, fitting your requirement.
* **Clear & Concise:** They are easy to understand, avoiding unnecessary jargon.
* **Targeted:** Each version has a different focus to suit various needs (General, Informative or Practical).
* **SEO-friendly:** They contain relevant keywords like “信件格式” (letter format), “書信” (letter), and terms relating to formats.

I recommend choosing the description that best fits the overall tone and the content of your blog. Good luck!