With Continuity Camera in macOS Mojave/Big Sur/Catalina, you can use your iPhone or iPad to directly import photos or document scans into a file on your Mac. It connects your Mac to your iOS or iPad OS device, which needs to be running iOS 12 (or later) or iPadOS 12 (or later).
To use Continuity Camera, you need to be signed into the same Apple ID on both your Mac and iPhone (or iPad). Both need to be connected to the same Wi-Fi network with Bluetooth enabled.