When you move home, you must report the change of your address to the National Population Register (folkeregisteret), within 8 days of your move. The National Population Register is managed by the Norwegian Tax Administration (Skatteetaten).
Different rules apply for how you should register your move and change of address, depending on where you move to/from, for example whether you move within Norway, within the Nordic countries or to countries outside the Nordic countries.
Moving to Norway
If you move to Norway and intend to stay more than 6 months, you must report your relocation to the Norwegian Tax Administration within 8 days of your arrival in Norway .
Moving within Norway
You must report your change of address to the Norwegian Tax Administration within 8 days of your move. You should also notify the Norwegian postal service of your change of address.
Read more about Moving home – NORWAY
Source: norge.no / Norway Today