The registration for the Import One Stop Shop in Germany is not done directly via the website of the BZSt, but since 01.04.2021 online via a portal through which data is exchanged with the BZSt: My BOP. A certificate file is required for logging in. Everyone who is already a user of the ELSTER portal should already have this. The file has the extension .pfx, so that you can easily find it on your computer or in the cloud if it has been misplaced.
Source: taxdoo.com
