X – “X” as a signaturerefers to a cross that is printed in lieu of an individual’s signature. A signature is required to authenticate deeds. Typically, individuals sign their full names when executing legal documents. Sometimes, however, individuals use only their initials or other identifying mark. For illiterate, incompetent, or disabled people, this mark is often the letter X. Documents signed with an X sometimes raise questions as to their validity and enforceability.