Mortuary Service Administration Act Article 61

Adults and those with such capacity may make a will beforehand or do it by filling out a letter of intent on funeral matters for after his death while still alive.Families or contractors handling the funeral matters shall respect the will or the letter of intent of the deceased in the preceding paragraph.
中文原文 殯葬管理條例第61條
成年人且有行為能力者,得於生前就其死亡後之殯葬事宜,預立遺囑或以填具意願書之形式表示之。
死者生前曾為前項之遺囑或意願書者,其家屬或承辦其殯葬事宜者應予尊重。

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