Where you need it
The number is used in tax, insurance and healthcare systems, as well as for trusted profiles. The number itself does not give a permit to stay, work or free treatment.
How to get
If the number has already been assigned, it is not necessary to re-obtain it. When the address is registered, it is assigned automatically. If registration is not possible, a separate declaration with a real legal basis is used. The issue is free of charge; step-by-step order is in the linked instruction.