How do I know if someone logged into my Apple ID ?

Hello~ Just to ask…what would make you think perhaps someone had? Click on below and review…

Check your Apple ID device list to find where you're signed in - Apple Support

If you think your Apple ID has been compromised - Apple Support

~Katana-San~

If you never shared your Apple ID and your Apple ID has not been compromised and you are only currently using one Apple device, then no other device is using your Apple ID.