What is End-to-end encryption?
A way of scrambling messages so only you and the person you're talking to can read them — not the app company or anyone in between.
With end-to-end encryption (E2EE), a message is scrambled on your device and can only be unscrambled on the recipient's device. Think of a letter in a locked box that only the recipient's key opens, versus a postcard anyone can read. Signal, WhatsApp, and iMessage use it by default; standard SMS text messages do not. Note that E2EE hides content, not necessarily metadata — who you messaged and when.