Detailed description
If you have a residence permit, you initially have a temporary permit to live and work in Germany. If you have already lived and worked in Germany for an extended period, you can apply for a settlement permit under certain conditions.
The settlement permit is a permanent residence permit. It allows you to work and live anywhere in Germany, and there are no additional requirements.
When and at which competent authority you can apply for a settlement permit depends on the reason for your previous residence permit.