I am going through hell and more to get a child support for my 2 small children, my soon to be ex husband doesn't want to pay and he is lying about how much he makes and because he is illegal no body can prove how much he makes.
I heard something called "garnished salary" does anyone know about this?
Can I ask the court to do this in my case?
Please help me.

Yes but it has to be proven that he works, where he works and how much he makes.
If his boss is lying about how much he makes it is harder to do.
If he is working under the table it seems to be harder to prove.
Best thing to do is go through the court system and tell the Judge everything you know.
Sometimes they will investigate for you.

I hope you have an attorney who can assist you in getting to the truth of your husband's earnings. It could get involved and be expensive.

Since he has to work under the table, his working at all is illegal and no boss is going to sign court papers that even says he works. Part of the trouble of being illegal to work in the US.

There is little you can do, excpet keep finding where he is working and having them served with papers .