FCC Registration Number (FRN)
Before the exam, you have to register with the American telecommunications authority FCC via the so-called Commission Registration System (CORES) and create an account via this link: https://apps.fcc.gov/cores/userLogin.do
The creation of the account must be confirmed via an e-mail that you will receive. After that, you can enter further data and apply for an FCC Registration Number (FRN), which is mandatory for the exam.
It is very important that you enter your US postal address as your address when registering with the FCC and not your residential address in Germany or wherever you live. If you don't have any relatives or friends in the US, you can also use one of the many mailbox and address services (e.g. USA2Me.com). You just have to make sure that the companies also forward letter mail (Postal Service), which not all of them do, or only under certain conditions. To do this, you have to fill out certain forms and go through an authentication process. You can find more information about this from the relevant providers.
If you do not live in the US, the name of the contact person should be given in the form c/o first name last name, for example: “c/o Carl Muller” with a comma and then the street in the address field.
Furthermore, you should definitely enter a permanent e-mail address, because all communication with the FCC is done electronically via the Universal Licensing System (ULS) and via e-mail.
After passing the exam, you can access your license data via your FC account and, for example, print or extend your license or apply for a vanity call sign.