Usually, NADA Germany processes TUE applications from athletes at national level, more specifically athletes who are member of a testing pool of NADA Germany (ATP, NTP, TTP) or player of high German leagues in some team sports. International athletes and athletes who are member of an international testing pool (RTP) should address their TUE application directly to their responsible international federation (IF).
Athletes who were already granted a TUE by NADA Germany and who want to participate in international competitions must have their TUEs approved by their respective IF. Depending on the IF, the process of approval can be handled differently. Some federations approve TUEs of NADA Germany automatically, others demand a comprehensive medical documentation in addition. Therefore, it might make sense to apply for a TUE directly to the IF, even if an athlete is not a member of an international testing pool, e.g. before international competitions.
If there is any uncertainty to which anti-doping organisation athletes should address their application, they can contact NADA Germany for help.