I am going to stay in Norway for longer than six months. What do I do?


Then you may be entitled to get a national identity number. 

The Norwegian Tax Administration assigns national identity numbers and decides whether you meet the conditions for being registered as a resident in Norway. If you are assigned a national identity number, you should use your national identity number instead of your D number (external website)

Suppose you have been granted a residence permit for six months or more, and you think that you should have been registered as a resident in Norway and received a national identity number instead of a D number. In that case, you can report a move to Norway (external website).