Enforcement Rules of the Labor Pension Act Article 29

Employers shall inform their employees of their monthly contribution to labor pension by listing payments on their salary statements or in other written form or by electronic means. Those who contribute voluntarily shall also be informed of their payment sums with a receipt at the end of the year.
中文原文 勞工退休金條例施行細則第29條
雇主應將每月為勞工所提繳之退休金數額,於勞工薪資單中註明或另以其他書面方式或以電子資料傳輸方式通知勞工。
勞工自願提繳之退休金數額,亦應一併註明,年終時應另掣發收據。

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