If you are seeking to pursue an individual doctorate in a doctoral subject, you should first apply to the doctorate committee of the school in question for acceptance („Annahme“) or admission („Zulassung“) as a doctoral candidate, after consulting your supervisor. Please contact the school’s doctorate committee administration directly. A timely enrolment following acceptance or admission by the doctorate committee is recommended. 

Information on the differences between acceptance, admission and enrolment can be found on the website Academic Career Paths (cf. Starting the doctorate right).