In Illinois what does "properly served" mean? Is regular mail, not certified, considered "properly served"?

For a debt, a lawsuit for a judgement ? I ask since service varies not only by state but by what is being served.

For a debt, a lawsuit for a judgement ? I ask since service varies not only by state but by what is being served.

Was sent a text messages at 10:17 am saying I had court to be evicted at 9:30 In maywood il. I was not served nor did I get any certified mail is this allowed. Can I get throw out my apartment since I missed my court date & not known about it