Signal is a private messaging app. It is intended to be simple enough to be usable by everyone in your family. It is probably the easiest-to-use secure messaging app.
Signal has all the features of a modern messaging app. It supports encrypted text messaging, voice calls, and video calls. You can also create messaging groups.
I like Signal because it’s available for all major platforms (Android, iOS, Mac, Linux, and Windows).
Signal is open source, and well regarded in the privacy community. The app contains no ads or trackers. However, Signal does require a phone number to use the app. If you need more privacy in your messaging, Session is a better choice.
Signal is run by an independent nonprofit. They claim that they “never have access to any of your communications and never store any of your data”. They also say:
We’re not tied to any major tech companies, and we can never be acquired by one either. Development is supported by grants and donations from people like you.
Quote from Signal website
Session may suit someone avoiding phone numbers, but calling it better for privacy feels too broad. That depends on what they’re trying to keep private.