⦁ A DNI (if you're an Argentinean resident or citizen or have a work visa)
⦁ A visa
⦁ A CUIL number (equivalent to a social security number in the United States)
I've been advised by several people that the best way to earn money in Argentina is to open up a business. If you have the money to do this then I highly recommend it, but keep in mind that if your business flops, there is no form of government bail out (like bankruptcy).
I've been actively looking for work in the administrative field, which is the type of work I used to do in the States, but many posts have age and gender requirements.