Here are a few options for a WordPress post_tag description, catering to different styles and use cases. Choose the one that best fits your needs:

**Option 1: Concise & Practical**

* **Title:** 0800 (八百)
* **Description:** 0800 免費電話號碼。 [0800 mianfei dianhua haoma.] (0800 free phone number.)

* **Use Case:** Clear and straightforward for posts related to phone numbers and customer service.

**Option 2: Slightly More Descriptive**

* **Title:** 0800 (八百)
* **Description:** 提供免費服務的0800電話號碼。 [Tigong mianfei fuwu de 0800 dianhua haoma.] (0800 phone numbers that offer free services.)

* **Use Case:** Emphasizes the free aspect of the phone numbers and could be useful for SEO keywords.

**Option 3: Explanatory (If further detailed for your audience is needed)**

* **Title:** 0800 (八百)
* **Description:** 在台灣和其他地方使用的免費電話號碼，通常用於客戶服務或資訊查詢。 [Zai Taiwan he qita difang shiyong de mianfei dianhua haoma, tongchang yongyu kehu fuwu huo xinxi chaxun.] (Free phone numbers used in Taiwan and other places, typically for customer service or information inquiries.)

* **Use Case:** Provides more context, making it helpful for understanding the general use of 0800 numbers.

**Option 4: Focus on Keyword Use**

* **Title:** 0800 (八百)
* **Description:** 0800 號碼, 免費, 客戶服務, 電話, 資訊。 [0800 haoma, mianfei, kehu fuwu, dianhua, zixun.] (0800 number, free, customer service, phone, information.)

* **Use Case:** Optimized for search engines by including relevant keywords. This focuses on improving visibility.

**Key considerations when choosing a description:**

* **Target Audience:** Who are you writing for? Tailor the language to their level of understanding.
* **Post Content:** Does your post revolve around specific elements related to 0800 numbers? If so make the description match.
* **SEO:** Include relevant keywords in your descriptions to help them rank better in search engine results. Consider the specific search terms your target audience is likely to use.
* **Brevity:** Keep the description clear and concise. WordPress tag descriptions generally don’t need to be long.
* **Consistency:** Use the same translation of “0800” (八百) consistently.
* **Context** Do you want the description to pop-up to visitors, or are you primarily optimizing it?