Presidential and Vice Presidential Election and Recall Act Article 59

Qualified voters shall vote by using a voting marker prepared by the election commission to select one pair of candidates by marking the circular symbol in the column labeled “select”.After selecting a pair of candidates, the elector shall not show the ballot to any other person.Special municipality and county (city) election commissions shall have the voting marker specified in Paragraph 1 made according to the specifications determined by the Central Election Commission.
中文原文 總統副總統選舉罷免法(新840809制定)第59條
選舉之投票,由選舉人於選舉票圈選欄上,以選舉委員會製備之圈選工具圈選一組。
選舉人圈選後,不得將圈選內容出示他人。
第一項圈選工具,由直轄市、縣(市)選舉委員會依中央選舉委員會規定之式樣製備。

English translation for reference only; the Chinese text prevails. Not legal advice.