Most phones will work in argentina as long as they are GSM not CDMA. GSM means they use a chip. Some companies like Verizon in the US are CDMA. Those phones will not work here. Below is a list of the frequencies used here. Just look at the phone's specs and make sure that the frequencies are included on the list.
GSM 850, GSM 1900
UMTS 850, UMTS 1900
LTE 700(28), LTE 1700(4), LTE 2100 (4)
And here is a website where you can put any cell phone model in and see if it will work in Argentina.