If you are travelling to Germany for Work you need to apply for a National Visa.
The German Mission usually issues visa up to 6 months. After your entry in Germany you should make an appointment with your Foreigners Office to apply for a residence permit.
General issuing conditions are;
How to apply
Step 1
Appointment request with German Mission
You need to take an appointment for the visa application at the German Mission and carry all the documents as per the checklist.
Step 2
Decision
If approved the German Mission will issue a visa upto 6 months.
Step 3
Entry
You can travel to Germany with the visa issued.
Step 4
Appointment for Residence Permit
After your entry in Germany you need to make an appointment with your Foreigners Office to apply for a residence permit. If you have submitted all the required documents and fulfilled the general issuing conditions, you will receive a residence permit.