A National Visa (or Category D visa) is a type of German visa. It lets you enter Germany to work, study or start a business. It’s valid for 3 to 12 months.1
You must apply for a National Visa at the German embassy or consulate in your home country. When you arrive in Germany, you must convert your National Visa into a residence permit at the Ausländerbehörde.
The Schengen visa is not a National Visa.