Signal
If you want something that is considered private, then Signal is probably the way to go.
When it comes to its user interface, it’s not as friendly as other options on the list, at least not until you get a hang of it. However, it’s a very secure app to use for messaging. Absolutely everything you do or share on Signal is end-to-end encrypted. Plus, it’s got the option to send disappearing messages if you want.
Besides these security features, Signal works like any other instant messaging app. You can send and receive texts and other type of media. Plus, you can keep your friends and family up to date with your life by sharing stories.
And if you want something more personal, you can just voice or video call any of your contacts from anywhere in the world.