Regulations for the Implementation of Annuity Insurance under the Labor Pension Act Article 23

Where workers voluntarily pay additional annuity insurance premium, the employer shall inform the insurer and may withhold the amount from their wages for payment to the insurer along with the portion responsible by the employer. Where the workers are unwilling to make payment, they shall notify the employers, and the employers shall notify the insurer to cease processing the portion of voluntary payment.
中文原文 勞工退休金條例年金保險實施辦法第23條
勞工自願另行提繳年金保險費者,雇主應通知保險人,並得自其工資中扣繳,連同雇主負擔部分,一併向保險人繳納。
勞工不願提繳時,於通知雇主後,由雇主通知保險人,辦理其自願提繳部分停止提繳。

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