Labor Insurance Act Article 65-1

The insured person or his/her beneficiary who conform to the claiming criteria of pension benefit should fill in an application and attach the related documents to apply to the insurer.When the insured person or his/her beneficiary in previous paragraph has been examined by insurer as qualified, the pension will be issued monthly from the month of the application until the month of pension termination.In case the beneficiary of survivor's pension doesn't submit application on the month they qualify for the benefits, the insurer should reissue the benefits to those who are entitled tracing back to five years before they submitted the application. However, for the part which already claimed by other beneficiary would not be included.
中文原文 勞工保險條例第65-1條
被保險人或其受益人符合請領年金給付條件者,應填具申請書及檢附相關文件向保險人提出申請。
前項被保險人或其受益人,經保險人審核符合請領規定者,其年金給付自申請之當月起,按月發給,至應停止發給之當月止。
遺屬年金之受益人未於符合請領條件之當月提出申請者,其提出請領之日起前五年得領取之給付,由保險人依法追溯補給之。
但已經其他受益人請領之部分,不適用之。

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