How to detect that my iPhone has been backed up with iTunes?
Does that person know your passcode?
If not, then no.
You need passcode or fingerprint before the phone will trust the computer.
From comments - If they did know the passcode, there is no way to tell.
Giving someone your passcode or Apple ID password is almost the same as giving them your ATM card &amp; PIN, if not worse. They can do what they like, because every system they interface with will think it is you.