Mo. Rev. Stat. § 486.645: Limitation on notarial acts, principal requirements — disqualification of notary, when — nonnotarial fee permitted, when.

1. A notary shall perform a notarial act only if the principal:

(1) Is in the presence of the notary at the time of notarization;

(2) Is personally known to the notary or identified by the notary through satisfactory evidence;

(3) Appears to understand the nature of the transaction requiring a notarial act;

(4) Appears to be acting of his or her own free will;

(5) Signs using letters or characters of a language that is understood by the notary; and

(6) Communicates directly with the notary in a language both understand.

2. A notary may certify the affixation of a signature by mark by a principal on a document presented for notarization if:

(1) The mark is affixed in the presence of the notary and two witnesses disinterested in the document;

(2) Both witnesses sign their own names beside the mark;

(3) The notary writes below the mark: "Mark affixed by (name of signer by mark) in the presence of (names and addresses of two witnesses) and the undersigned notary pursuant to section 486.645, RSMo"; and

(4) The notary notarizes the signature by mark through an acknowledgment, jurat, or signature witnessing.

3. A notary shall be disqualified from performing a notarial act if the notary:

(1) Is a party to or named in the document that is to be notarized;

(2) Will receive as a direct or indirect result any commission, fee, advantage, right, title, interest, cash, property, or other consideration exceeding in value the fees specified in section 486.685; or

(3) Is a spouse, domestic partner, ancestor, descendant, or sibling of the principal, including in-law, step, and half relatives.

4. Notwithstanding subdivision (2) of subsection 3 of this section to the contrary, a notary may collect a nonnotarial fee for services as a signing agent if payment of such fee is not contingent upon the signing, initialing, or notarization of any document.