I think both SIU and Westerm IL have a minimum GPA/ACT combo they want students to have for admission; and if you have that, you are automatically admitted.
No essays required for these schools, but I believe IL State gives you the option of submitting an essay of you think it help your situation.
Go to their websites and look under Admissions, and Undergraduate Admissions, and see what the grade/test score requirements are.
My D also applied to SIU-C but hasn’t decided if she’s going there yet. Fwiw, I really like that school, I think it’s an underrated university with lots and lots of opportunities for an undergraduate.
Best of luck to you.