No mortgage, deed or other conveyance of the homestead by a married person shall be valid without the voluntary signature and assent of the husband or wife, which must be shown by his or her examination before an officer authorized by law to take acknowledgments of deeds, and the certificate of such officer upon, or attached to, such mortgage, deed, or other conveyance, which certificate must be substantially in the form of acknowledgment for individuals prescribed by Section 35-4-29.
Ala. Code § 6-10-3 (1975)