Electronic Signatures Act Article 9

The time of dispatch of an electronic record occurs when it enters the information system outside the control of the originator, unless otherwise agreed by the parties or otherwise announced by a government agency, in each case, such agreement or announcement shall be followed.Unless otherwise agreed between the parties or announced by government agencies, the time of receipt of an electronic record is determined as follows:(1) if the addressee has designated an information system for the purpose of receiving electronic records, receipt occurs at the time when the electronic record enters the designated information system; or if the electronic record is sent to an information system that is not the designated information system, at the time when the electronic record is retrieved by the addressee.(2) if the addressee has not designated an information system, receipt occurs at the time when the electronic record enters an information system of the addressee.
中文原文 電子簽章法第9條
電子文件以其進入發文者無法控制資訊系統之時間為發文時間。
但當事人另有約定或行政機關另有公告者,從其約定或公告。
電子文件以下列時間為其收文時間。
但當事人另有約定或行政機關另有公告者,從其約定或公告:
一、如收文者已指定收受電子文件之資訊系統者,以電子文件進入該資訊系統之時間為收文時間;電子文件如送至非收文者指定之資訊系統者,以收文者取出電子文件之時間為收文時間。
二、收文者未指定收受電子文件之資訊系統者,以電子文件進入收文者資訊系統之時間為收文時間。

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