Code of Civil Procedure Article 145

Where service is to be made in a foreign country, it shall be effectuated by the competent authorities of such country requested to do so, or the relevant R.O.C. ambassador/minister envoy/consul, or other authorized institutes or organizations in that country.Where service cannot be effectuated in accordance with the provision of the preceding paragraph, it may be effectuated by dispatching the paper to be served with by registered and receipt requested mail. The returning receipt requested of such mail shall be included in the dossier.
中文原文 民事訴訟法第145條
於外國為送達者,應囑託該國管轄機關或駐在該國之中華民國使領館或其他機構、團體為之。
不能依前項規定為囑託送達者,得將應送達之文書交郵務機構以雙掛號發送,以為送達,並將掛號回執附卷。

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