There are two types of travelers, those who unplug for peace and those who use technology in their travel. Forbes has a list of the best apps for 2016. They are the following:
Trip Case – organize multiple flihts, hotel reservations and plans
Snapchat – Share quick photos or videos with other users
BringFido – Maps out dog parks and pet-friendly hotels
Bravolo – 13-language phrasebook
Currency – keeps track of your finances in multiple countries
CityMaps2Go – Downloadable maps and guides
Before you leave, download all the apps you think you will need in case you don’t have Internet to do it. Also, check to see if the country you are going to has some apps censored.
Apps I would suggest is WhatsApp, to communicate over wifi and any language app that you can use without the Internet.