Yes, you should upload your documentation to the online application portal, where you submitted your application for admission. Documentation includes diplomas, transcripts, English language test results etc.
Applicants from some countries are required to submit documentation in hard copy. Check if this applies to you here.
Documentation submitted by post, should be sent to:
Admissions Office
UiT the Arctic University of Norway
Postbox 6050 Langnes
9037 Tromsø, Norway