Detailed description
Depending on your nationality, you will need a national visa for stays in Germany longer than 90 days. The procedure and the requirements also depend on the purpose for which you want to stay in Germany (e.g. gainful employment, family reunification, studies and training).
Citizens of EU countries and some other countries (e.g. Iceland, Liechtenstein, Norway, Switzerland, USA, Canada, Australia) do not need a visa. As a rule, they can also enter the country for a longer stay without a national visa and apply for their residence permit at the immigration authorities after entering the country. You can find a complete list of countries with an indication of the respective visa requirements on the website of the Federal Foreign Office. In certain cases you have to prove knowledge of the German language.
The issuing of the national visa is based on the same regulations that also apply to the issuing of the residence permit, which you must apply for in Germany after the visa has expired (e.g. residence permit, EU Blue Card).