Meaning
A mobile phone shown with an off symbol or the word OFF, usually on a square sign. It means the phone is switched off, like the reminder signs in theatres and exam rooms.
Use it to announce a digital detox, a family dinner without screens or a weekend when nobody can reach you: “Camping till Sunday 📴 call my sister if it’s urgent” It is stronger than 📳 or 🔕, which still keep the phone on.