Mich. Comp. Laws § 440.3401: Liability; signature.

Sec. 3401.

A person is not liable on an instrument unless ( i ) the person signed the instrument, or ( ii ) the person is represented by an agent or representative who signed the instrument and the signature is binding on the represented person under section 3402.

A signature may be made ( i ) manually or by means of a device or machine, and ( ii ) by the use of any name, including a trade or assumed name, or by a word, mark, or symbol executed or adopted by a person with present intention to authenticate a writing.