Ill. Admin. Code tit. 80, § 1.145
Parties may choose to represent themselves, be represented by an appropriate association, or be represented by an attorney licensed to practice law in the State of Illinois. An attorney representing a party shall file a written notice of appearance with the Commission identifying the attorney by name, address, telephone, facsimile number, email address and attorney registration number.
(Source: Amended at 42 Ill. Reg. 16395, effective September 1, 2018)