When you exit the flat setting, will it be displayed on your mobile phone?

There will be a prompt tone when you exit the phone synchronization, but see if you have turned on the phone prompt tone. If the prompt tone is turned on, there will be a prompt.

One account can log in to multiple Apple accounts. When one of the devices logs off, there is no prompt on the phone. But you can log in to your mobile phone and click Settings to enter your account. Click iTunesstore and appstore, click appleid, and then select View appleid, where you can see the devices currently logged in.