How to find a lost Apple device offline?

Apple’s ‘Find My iPhone’ service has been rebranded as ‘Find My’ with iOS 13 and macOS Catalina. And one of its pre-eminent features is that it will let you locate your devices even when they are offline.

Apple describes their offline location support in their new Find My app as, “Locate a missing device even if it’s not connected to WiFi or cellular using crowd-sourced location. When you mark your device as missing and another Apple user’s device is nearby, it can detect your device’s Bluetooth signal and report its location to you. It’s completely anonymous and encrypted end-to-end, so everyone’s privacy is protected.”