Over the years, a lot of us have had quite a few iOS devices and Macs signed in and out of our iCloud accounts. Apple provides a built-in way to see what devices are signed in to an iCloud account, and they also provide some additional details about the devices. As an added bonus and security measure, you can remotely sign devices out of iCloud.
This is a useful feature for removing devices that you’ve gotten rid of over the past several years, and in worst case scenarios, devices that have been stolen. This isn’t a feature that you need very often (hopefully), but it’s a good practice to check which devices are logged in every year or so, depending on how often you upgrade to new devices.
From iOS, go to Settings → iCloud → Tap your name → Devices. Tap on a device to see additional information (model, serial, OS version, etc.). You can tap Remove from Account to remotely remove a device from your account.
On the Mac, go to Settings → iCloud → Account Details → Devices.
On the web, go to iCloud.com, and click Settings → My Devices.
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