Continuity

Refers to features — such as Handoff, Instant Hotspot, phone calling and SMS — that let you seamlessly move between your Mac, iPhone, iPad, iPod touch and Apple Watch, or use them together. For example, with Handoff you can start a document, email or message on one device and pick up where you left off on another device.

To use Continuity features, your devices must meet system requirements. See the Apple Support article Continuity features and requirements on Apple devices.