If you are going to visit Norway, you can apply for a visitor visa (Schengen visa). You must show that you have enough money for your trip and stay in Norway. If you can not pay yourself, the person you visit must guarantee financially for you.
How to apply for an extension of a visitor's visa
If anything happens requiring you to prolong your stay in Norway or the Schengen area beyond the expiry of your visitor's visa, you can apply to extend your visa.
