If you need to complete your schooling in Germany, you have the following options:
If you are younger than 21, we strongly recommend that you go to a German high school and finish the years you have left (you could also attend an evening school, Abendgymnasium, or a Kolleg, a preparatory school).
If you are older than 21, you can go to:
Evening schools (Abendschule): institutions for adults to catch up on school-leaving certificates;
Adult education centers (Volkshochschule): there you can take courses on all kinds of topics but also catch up on school certificates. If you are interested in going to a Volkshochschule we suggest you get in contact with them directly. Find the closest one to where you live here.
To read more about what comes next after finishing high-school, read our article on what you should know about the German educational system.