Screen Sharing.app is a bundled application that lets you observe or control a remote computer. Typically, the computer is already under your control and either has Screen Sharing enabled in the Sharing settings or a VNC server running. But having a knack as a Mac whisperer doesn’t go unnoticed by family and friends. There are times when it’d be really handy to be able to hop on a friend or family member’s computer to actually see what they’re trying to describe instead of talking thru it. There are 3rd party services out there that can accomplish this but require downloading, installing, and configuring. This feature just works* as long as the remote computer has an iCloud account setup on it, which at this point most do.
*Of course there are exceptions. Firewall restrictions may not allow the traffic thru.
To start a session launch the Screen Sharing.app via Spotlight (command-space) and typing “Screen Sharing” or by navigating to /System/Library/CoreServices/Applications/Screen Sharing.app
Once it launches you’ll be presented with a field that asks for a hostname or Apple ID
Start typing a name in your Contacts. If you have contacts that have Apple IDs they’ll show up in blue text, similar to Messages. It may take a few seconds for the names to be identified as Apple IDs and have the color change. If you know the Apple ID email address you can enter that directly as well.
Click the “Connect” button and the remote machine will get prompted to allow you to connect. Note, the prompt to connect will appear on all the machines that are setup with that Apple ID.
If the Apple ID of the instigating connection is in the receiver’s contacts, when “Accept” is clicked it will immediately allow Observe abilities of the remote screen. If the Apple ID trying to connect doesn’t match a contact on the receiving machine the receiver will get this prompt.
Upon connection, by default the microphone is engaged so you can talk as well as see the remote screen. The microphone can be muted from menu bar extra if desired. While connection is active the menu bar extra flashes to remind of that connection.
If you need to control the computer instead of just observe you can request control from the Screen Sharing window. Once Control is asked for, the remote machine gets a prompt to allow control.