Smart move, public transport is fine between the big cities but once you want to hit the highlands or the coast at your own pace having your own wheels is a total game changer. Bring your passport, a valid driving licence from your home country, and an IDP is worth having even though a lot of rental desks won't strictly ask for it. Book online before you fly so you can lock in a better rate and avoid the inflated airport walk-up prices. To check options and rent a car in Peru just browse the listings on this site
https://getrentacar.com/en-US/peru .