I'm not a legal resident of the US. I currently work for McDonalds and gave them a face Social Security Number to get hired. McDonalds now wants to make me a manager, but they need to run a background check first. What does this mean? Will they check my citizenship status?
They are going to run your social security number and name through a data base to see if you have any criminal record and other stuff.
They will discover that you lied, and they will have to fire you.
It is illegal to knowingly hire someone who cannot legally work in the US.
Not to mention the fact that you completed federal legal documents and they are submitting data under the Social Security number you gave them.
McDonald's is facing thousands of dollars in fines just for having you work there.