Going digital doesn't mean going paperless entirely — a few documents are still worth having ready in more than one format.
At minimum: your passport, your home driver's license, and your IDP, ideally saved both on your phone and printed as backup. Add your rental confirmation, travel insurance details, and a copy of your itinerary saved offline in case you lose signal.
Screenshot or download every digital document before you travel, and email copies to yourself as well. If your phone dies or your bag goes missing, you'll still have access to what you need from any device.
Keep your license and IDP together, digitally or on paper — the IDP only means anything when shown alongside the license it translates. Entry, driving, and car-rental requirements can change and vary by destination. Always confirm current rules with the relevant embassy, consulate, or local authority before you travel.