This situation may be that your Apple ID password has been leaked, or this is not your mobile phone. If it is not your mobile phone, please return it to the owner as soon as possible. If the password is leaked, some measures can be taken.
1. First enter the Apple id management center, enter "Apple-My Apple ID" in Baidu, and then click to open the first webpage.
2. After entering the URL, enter my Apple ID management page.
3. After entering the management page, find the "Manage your Apple ID" option.
4. Click this button when you find the "Manage Your Apple ID" option.
5. Enter the ID for registration in the input box of the pop-up window, that is, the email address.
6. After entering the ID, click "Forgot your password?" Options.
7. Then, go to another new page and click Next.
8. After clicking Next, select the way to retrieve the password. Take e-mail retrieval as an example, click E-mail, click Next, and finally log in to check the e-mail.