apple id

Yes, it does mean what you say and more. Change your password to a strong one.

See Change your Apple ID password https://support.apple.com/en-us/HT201355 

And, here is What to do after you change your Apple ID or password https://support.apple.com/en-us/HT204071

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Also, if you can, Check your Apple ID device list (https://support.apple.com/en-us/HT205064) and remove any device that shouldn't be signed in using the steps in the link.

Your friend could not have used your device without your Apple ID. You should change your Apple ID password. You may want to change other non-Apple account passwords just to be safe.

In the future, you should never give others access to your devices, Apple ID or passwords.