Minn. Stat. § 201.056: SIGNATURE OF REGISTERED VOTER; MARKS ALLOWED.

An individual who is unable to write the individual's name must sign a registration application in the manner provided by section 645.44, subdivision 14. If the individual registers in person and signs by making a mark, the clerk or election judge accepting the registration or update must certify the mark by signing the individual's name. If the individual registers or updates a registration by mail and signs by making a mark, the mark must be certified by having a voter registered in the individual's precinct sign the individual's name and the voter's own name and give the voter's own address.