Do I need to submit my W2-C with all my state returns or only for the state it matters?

I had taxes held for two states IN and IL for 2021. I later got a W2-C in which only Indiana's county income (box 18) was corrected, everything else remained the same. I have already filed my federal return, roughly a month before the W2-c was issued. My questions are as follows:

1. Do I need to send my W2-c to Illinois also?
2. Do I need to file an amendment and send it to IRS for federal return?

Also, when sending the W2-c, do I send the complete page with one return, or do I tear one small section like the main W2?

Please feel free to ask for clarifications.