The US Treasury made and minted several $500.00 bills in the past but no longer do.
The $500.00 bill was made and rolled off the printing presses in the year 1945 and then was made until 24 years later which is when they discontinued and stopped making the $500.00 bill.
In the year 1969 the US Treasury stopped making the $500.00 bill.
If there are still some 500 dollar bills in existence they still remain legal tender and can be used to pay for things and buy things with.
Although you're likely to only find the 500 dollar bills with collectors or have to pay more than 500 dollars to get the 500 dollar bills because they don't make them anymore.