(A)   The corporate seal of the city shall be the same as that heretofore provided and used by the city. It shall be circular in form, with the words “City of O’Fallon, Illinois” in the exterior circle, and the word “Seal” in the center.
   (B)   The corporate seal shall be used as such seal in all cases provided for by law or by the ordinances of the city, and in all other cases in which, by law and custom, it is usual and necessary for the corporation to use a seal.
(1999 Code, § 10.20)