On 11 September, an article from Hogan Lovells explains that the Economic Operators Registration and Identification number, basically an ID number for customs purposes that is assigned by a customs authority to any businesses or people (aka economic operators) wishing to trade in the EU has just become (i.e. from 15 September) a mandatory field in any customs application for action (AFA). A customs Application for Action (AFA) must be submitted to a competent customs department designated by the Member State for customs to act at the borders on behalf of the right holder. The main purpose of AFA is to request customs to detain goods found to be suspected of infringing your intellectual property rights (IPR).
https://www.jdsupra.com/legalnews/eu-customs-enforcement-eori-number-now-64509/