65 ILCS 40/2
The president of any incorporated town to which this Act is applicable may certify such fact to the recorder of deeds of the county in which the incorporated town is located. The recorder of deeds shall record this certification and shall immediately transmit the certification to the Secretary of State together with his certificate of recordation. If it appears from the certification and such other supporting evidence as may be required by the Secretary of State that the incorporated town is one which is described by Section 1, the Secretary of State shall file the documents, issue his certificate of approval and enter the incorporated town in the register of municipalities required by Section 2-1-5 of the "Illinois Municipal Code", approved May 29, 1961, as amended.
65 ILCS 40/2