Administrative Procedure Act Article 95

An administrative disposition may be rendered in writing, orally or in any other form, unless the law requires that it must be formal.In the case of an administrative disposition rendered other than in writing, the authority rendering the disposition may not refuse to have it made in writing if the person subject to it or a person affected thereby has a good cause to request so.
中文原文 行政程序法第95條
行政處分除法規另有要式之規定者外,得以書面、言詞或其他方式為之。
以書面以外方式所為之行政處分,其相對人或利害關係人有正當理由要求作成書面時,處分機關不得拒絕。

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