Entrepreneurs from non-EU countries require a residence permit (Aufenthaltserlaubnis) or a settlement permit (Niederlassungserlaubnis) if they want to run a business in Germany on-site or if they are employed in Germany.
A residence permit is always limited in time, a settlement permit is unlimited. A settlement permit will usually be issued, if a non-EU citizen has been in possession of a residence permit for at least five years. Both residence and settlement permit are always issued for a specific purpose, usually for the purpose of self-employment or for the purpose of taking up employment in Germany. For more information, please also refer to the following site:
A residence or settlement permit will be issued by the local immigration office (Ausländerbehörde) in Germany. To enter Germany, a national visa is issued for the trip to Germany by the responsible German embassy in the applicant's home country or country of residence. This is then converted into a residence or settlement permit in Germany.
For more information on visa application and issuing, please refer to the following site:
However, there are exceptions for several countries. Citizens from Australia, Canada, Israel, Japan, New Zealand, South Korea, and the United States may enter and stay in Germany without a national visa (up to 90 days). The application for a residence or settlement permit for the purpose of self-employment or taking up employment can be filed at the local immigration office in Germany.
The German Federal Office (Auswärtiges Amt) has detailed information on visa requirements available. Please also refer to the following site: