Okla. Stat. tit. 16, § 16-34: Execution by mark

When real estate is conveyed or encumbered by an instrument in

writing by a person who cannot write his or her name, the person

shall execute the same by a mark, and the person’s name shall be

written near the mark by one of two persons who saw the mark made,

who shall write their names on the instrument as witnesses. In case

the instrument is acknowledged, then the officer taking the

acknowledgment shall, in addition to the other necessary recitals in

the acknowledgment, state that the grantor executed the instrument,

by inserting in the form of acknowledgment provided in Section 33 of

this title by individuals after the words "foregoing instrument" the

words "by the person’s mark, in my presence and in the presence of

____ and ____ as witnesses".