"Einschreibung" and "Immatrikulation" mean registration or matriculation at a university. To register, students have to go to the registrar's office or the student registration office, often known in German as "Studierendensekretariat". They generally have to present their Admissions or Acceptance Letter (Zulassungsbescheid) and their Higher Education Entrance Qualification (Hochschulzugangsberechtigung), generally a school-leaving certificate, like the Abitur or Fachhochschulreife. They also have to pay a registration fee.