Shadowing

Hello,

If your content synchronizes with iCloud, such as Messages, Photos, etc then whatever is shown on 1 iPad/iPhone will be displayed on the other devices signed in with your Apple ID. If this is a concern for you then I suggest changing your Apple ID password. Then any other device signed in with your Apple ID will require them to enter your new password. You could also lock your other iPads using Find My iPad (if you have Find My iPad enabled).

Change your Apple ID password - Apple Support

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

Hello,

Can you please elaborate more on your question?

Writing an effective Apple Support Community post