Why isn’t my stuff syncing between my Macs and devices?

iCloud can magic all your photos, emails, contacts, calendar events and so on from each of your Macs and iOS devices to the others. If content fails to materialise on a device, most likely you’re not logged in to iCloud on it, or you’ve used the wrong account, or haven’t turned on the service. Look in System Prefs > Apple ID (or iCloud) on your Mac; in iOS’ Settings, tap your name to see who you’re logged in as, then iCloud to see what’s set to sync. Also go to bit.ly/apple-sysstat for any faults at Apple’s end.