N.D. Cent. Code § 16.1-11.1-04: Voting by electors

Upon receipt of a mail ballot, an elector shall mark it, sign the return identification envelope, and comply with the instructions provided with the ballot. The elector may return the completed ballot to the county auditor by mail or, by the close of polls on election day, to any other place of deposit designated by the auditor. The elector may not deliver the completed ballot to an election board at a polling location. If the elector returns the ballot by mail, the elector shall provide the postage, and the ballot must be received by the officer by the close of polls on election day.