A mortgage of real property can be created, renewed, or extended only by writing, executed with the formalities required in the case of a grant of real property.
N.D. Cent. Code § 35-03-01
Mortgage of real property must be in writing - Formalities necessary
Official source: North Dakota Legislative Branch. Reproduced from public-domain North Dakota statutes; confirm against the official source for the current text. Not legal advice.