To register your ATV, visit a North Dakota Department of Transportation licensing office. You'll need to furnish your name, address, and the signature of at least one owner, along with the appropriate registration fees. Keep a copy of the registration as your temporary proof of registration until the original arrives in the mail. Once it arrives, the registration decal must be affixed to the ATV so that it's clearly visible.
Check out these Park River, ND ATV/OHV resources: