https://www.epo.org/en/service-support/faq/law-practice/list-professional-representatives-entry/do-i-need-submit-apostille
Do I need to submit an apostille certification of the copy of my ID with my request?
A certified copy of your valid passport or identity card is required. For the purposes of this request, official certification may be provided by an authority of a contracting state, an attorney-at-law or a solicitor (insofar as they are entitled to under the applicable law) or a professional representative before the EPO.