Is there a way to attach a form to SS such as IL 1040-ES and suggestions for the employee on what do
We have an employee that works in MO but lives in IL. They contacted us indicating they should have filled out a IL-1040-ES form because they had to pay taxes at the end of the year.
In Illinois, if you are having out of state income, you need to be making quarterly estimated payments on what taxes you should be paying to Illinois. The form that you have to fill out for that is IL-1040-ES. Filling out the estimated tax worksheet on that form will tell you what you need to be paying. You put in your expected income and expected taxes for other states as well as other expected credits to subtract from and you compute your estimated payments to Illinois. Missouri tax credits do reduce the estimated payments to Illinois significantly, however, for my