Install in this order, two weeks before departure:

  1. A visa checker that knows each family member's passport. Requirements differ per nationality, even in one household.
  2. A document scanner. Scan every passport now, while there is no deadline pressure.
  3. A shared storage folder. One folder per traveler, visible to the adults.
  4. The airline apps for your actual flights. Check-in documents live here.
  5. Google Translate with offline packs for the destination language.
  6. A currency app for fee math at visa-on-arrival counters.
Visa App Download Guide: What to Install Before a Family Trip Abroad
Image via Wikimedia Commons

Sources: U.S. State Department, IATA Travel Centre

What not to install: three different visa checkers, a "visa photo booth" app with a subscription, and anything that asks for passport numbers before showing a single useful screen. Six apps, installed early, beats sixteen apps installed at the airport.