"TP" means "taxpayer". Schedule IL-WIT, Illinois Income Tax Withheld, allows you to enter your withholding information in one place and calculate total Illinois withholding.
The program just wants you to verify the state withholding. If it is asking for the state, go ahead and enter IL. The withholdings should pull through from the input under the federal section.
If you are in a Review and see this error, enter the state in the place the error message provides rather than in the display of the form.
See here for another discussion of this issue.
See here for the instructions for Schedule IL-WIT.
[Edited 02/4/24| 3:00pm PST] and @2dogs17-- (edited)
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
