Enforcement Rules of Value-added and Non-value-added Business Tax Act Article 11-1

A business entity, selling electronic services to foreign individuals through a business entity which shall apply for taxation registration in line with Article 28-1 of the Act, applying for a zero business tax rate pursuant to Subparagraph 2 of Article 7 of the Act shall submit not only the documentary evidence prescribed in Subparagraph 2 of the preceding Article but also the documentary evidence of overseas use provided by a business entity which has already made the taxation registration pursuant to Article 28-1 of the Act.
中文原文 加值型及非加值型營業稅法施行細則第11-1條
營業人經由依本法第二十八條之一規定應申請稅籍登記之營業人銷售電子勞務予境外自然人,依本法第七條第二款規定適用零稅率者,除前條第二款文件外,並應檢附已依本法第二十八條之一規定辦理稅籍登記之營業人所提供在國外使用之證明文件。

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