Signal
Signal is far from the most popular end-to-end encrypted messaging app. But if your conversations are even the slightest bit sensitive or confidential, it may be your best bet. Not only does Signal encrypt every message you send, but it collects so little data that it hardly knows anything about you.
Because of that, it’s the first choice for journalists, privacy advocates and other security-conscious individuals. And just like other apps on this list, it lets you send messages or make audio calls internationally to other Signal users. (You may just need to have your call recipient download the app first.)
Get Signal here.