When you have a job, you need a tax deduction card or an exemption card. Be aware of the the tax information is personal. The Norwegian Tax Administration will send your tax registration to the employer electronically. If you are not registed, the employer will deduct 50 % tax.
Here you find information from The Norwegian Tax Administration regarding your tax.
The next year, you’ll receive your tax return pre-filled with information about how much tax you should have paid. You have to check if the amounts are correct. When you have submitted your tax return, you’ll receive a tax assessment notice. This will tell you whether you are due a tax refund or if you have to pay more tax.