One really easy way to view someone else’s screen or even control their Mac over the internet which is invaluable if you’re trying to help a relative troubleshoot their computer problems, is to launch Screen Sharing by searching for it with Spotlight then entering the Apple ID of the person you’re trying to contact.
If you or they don’t know it, just have them look in the iCloud pane of System Preferences. And, while you’re in that screen, make sure they have Screen Sharing enabled in the Sharing pane of System Preferences.
They'll be asked to grant you permission to view their screen, and they can also then click on the screen sharing icon in the menu bar and grant you the ability to virtually, remotely control their mouse and keyboard too.
They'll be asked to grant you permission to view their screen, and they can also then click on the screen sharing icon in the menu bar and grant you the ability to virtually, remotely control their mouse and keyboard too.