How do I find out what devices are using my Apple ID?

Answer

Sign in to your Apple ID account page, then scroll to Devices.
If you don’t see your devices right away.
Click View Details and answer your security questions.
Click any device name to view that device’s information, such as the device model, serial number, and OS version.

How To Remove Devices from Your iCloud Account | Maximize the Security of Your iPhone

Approve this iPhone ! go to one of your other devices signed in to icloud to approve this iphone

Why does it say my Apple ID is being used somewhere else?

Your Apple ID is being used to sign in [via some method] near [place that’s nowhere near you]. This may be the consequence of an old password breach elsewhere or one that just occurred.

What if my Apple ID is being used on another device?

Any other devices linked to the same ‌Apple ID‌ should display this popup notice on the screen if you sign out of iMessage or FaceTime on one device and then set up a new Apple device, erase and reinstall the operating system on a device you already own, and then sign back into your ‌Apple ID‌: “

How do I know if someone has hacked my Apple ID?

You receive an email from Apple notifying you that your Apple ID password has been changed or your account information has been updated, but you don’t remember making any changes. Someone other than you locked or put your device in Lost Mode.

Can I tell if someone has accessed my iPhone?

To find out which devices are signed in with your Apple ID, go to Settings > [your name]. To check if any further information has been added to your account using someone else’s Apple ID, sign in to appleid.apple.com with your own Apple ID and look through all of your personal and security data.

Can someone see my texts with my Apple ID?

If someone accesses your Apple ID on the web, they won’t be able to read or send your iMessages. However, if they log into your Apple ID on a device, they will be able to do so. Once someone logs into your Apple ID using their username and password, all of your iMessages (both sent and received through either their Apple ID or phone number) going back and forward are visible on a different gadget.

How do I remove an unknown device from my Apple ID?

If the device is already in use, you’ll need to contact the previous owner to have them log out of iCloud or go to https://www.icloud.com/find/ My Phone and erase it from their account, then delete it from your account.