Unless you take specific and non-trivial measures, communication over the Internet is not private. Text messages and other instant messaging, email, social media especially. Phone calls. Even if you use end-to-end encryption tools (PGP, Signal, OMEMO, Matrix encryption), someone who steals one of your devices may be able to get the messages.
If you want to be in private, meet in person. And, while you're at it, leave anything with a microphone somewhere else while you talk.