If you are the spouse of a service member and neither of you is a North Dakota resident, the income you earn while you are in North Dakota with the service member can be exempt from North Dakota income tax.
There is nothing to apply for in advance. Claim the exemption when you file, and give your employer your residency information so North Dakota tax is not withheld from your wages.
The service member’s military orders assigning them to North Dakota, and proof that you and the service member are residents of another state or territory.