UBER is indeed available in Buenos Aires although there is much controversy over it, as there has been around the world.
But, since September 2020, it was declared Legal.
In Buenos Aires, the company offers its services to all who download the application. Users can pay with a foreign credit card or in cash with Argentine pesos. Nothing bad will happen.
They have even developed new services such as Uber Comfort or Uber Eats.
You may have read about some violent episodes in which taxi drivers physically threaten UBER drivers and damage their cars claiming that this international company brings forth unfair competition. Nevertheless, this is a thing of the past. Thousands of porteños and tourists choose UBER as the cheapest, most reliable and safest way to move around the city.
Since the fares here are very low in comparison to those of other big cities, we do recommend you take UBER Comfort, because the cars are much nicer and you will be more comfortable.
Also, there are other options like using the CABIFY app that works as well as UBER. It is a bit more expensive, but 100% legal. Another option is Didi, fairly new.