Sign into Apple ID email from suspicious user
Can I know what device and where this was done?
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You won't know the exact device or where the signing occurred.
Check your device list to see if there is a device signed in that you don't recognize. You can remove the device using the steps in the article below. As a precaution, change your password.
Apple ID device list -Check to see where you‘re signed in. *
ASC YouTube for How to reset your Apple ID password
What to do after you change your Apple ID or password - Apple Support - I suggest doing this before you change your Apple ID or password.