I am so confused on how cellular works on he Watch. Can I leave my phone at home and go out with the watch and have cellular function for phone and texting?
To receive SMS, MMS, or push notifications from third-party apps on your Apple Watch Series 3 (GPS + Cellular), your paired iPhone must be powered on and connected to Wi-Fi or cellular, but it doesn't need to be nearby. You also need to be signed in to iMessage on your iPhone.