Firstly, you need a valid driver’s license. In most cases, you must have held it for at least one (1) year. You also need a credit (or debit, where accepted) card to pay for the rental and leave a deposit and the voucher received after your booking is confirmed.
When renting in a foreign country, you often need another form of identification, usually a passport.

This depends on where you would like to rent a car. Though you can rent a car at the age of 18 in many European countries and the states of New York and Michigan in the United States, in many locations you must be 21 to rent a car. You can conveniently check this by entering your age before clicking ‘Search now’.
Note that most rental suppliers charge an additional Young Driver Fee for renters under the age of 25, though this age varies by supplier and location. If you enter your age before searching, we include this fee in the total, allowing for the simplest comparison.

Though just a few years ago it was impossible to rent a car without a credit card, things have changed quickly. Many suppliers, especially global companies such as Avis, Dollar, Hertz, etc., allow renters to both pay and leave a deposit with a debit card (though the card must be a Mastercard or Visa).
If you do not have a credit card, be sure to check the Payment Policy section of the Rental Conditions prior to booking to see if the supplier accepts debit cards.