Minn. Stat. § 201.056
An individual who is unable to write the individual's name shall be required to sign a registration card by making the individual's mark. If the individual registers in person, the clerk or election judge accepting the registration shall certify the mark by signing the individual's name. If the individual registers by mail, the mark shall 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.