Three things: a driver's license, an ID and a payment method.
1 · A valid driver's license
At least one year old. This is the requirement that matters most: being old enough isn't enough, the license needs to have that year. In Uruguay it's called libreta de conducir; it's the same thing.
There's also a minimum age: 18 in Argentina and Mexico, 19 in Uruguay.
Your license has to be verified in the app before the rental starts. And if you're meeting the host to pick up the car, bring the original: photocopies, photos and loss reports aren't accepted.
2 · ID or passport
Your national ID or your passport both work, whichever you have at hand.
3 · A payment method
A credit or debit card, with enough balance or limit to cover the rental and the security deposit. The card doesn't have to be in your name, as long as you're listed as the driver on the booking.
What if I'm a foreigner?
Same requirements, same documents. You can rent with your home country's license, also at least one year old, and your passport as ID.
Before you book
Upload your personal details and your license in the app. Your profile goes through a verification and, once approved, you can book.