410 ILCS 130/210
(a) This subsection (a) applies to returns due on or before the effective date of this amendatory Act of the 101st General Assembly. On or before the twentieth day of each calendar month, every person subject to the tax imposed under this Law during the preceding calendar month shall file a return with the Department, stating:
(5) Such other reasonable information as the Department may require.
If a taxpayer fails to sign a return within 30 days after the proper notice and demand for signature by the Department, the return shall be considered valid and any amount shown to be due on the return shall be deemed assessed.
The taxpayer shall remit the amount of the tax due to the Department at the time the taxpayer files his or her return.
(Source: P.A. 101-27, eff. 6-25-19; 101-593, eff. 12-4-19.)