Whenever fingerprint or face biometrics are added to or deleted from your mobile device, you will get a notification. Moreover, in that case the feature will be disabled in the app. You will then need to re-enable Fingerprint,Touch ID or Face ID and confirm this with your identification code.
To make sure only your own fingerprint or face biometrics are registered, delete all the fingerprints and face biometrics and re-register just your own. Also set a screen lock.