В настройках моего iPhone чужой Apple ID

Greetings DenisChernov,

If there is a different Apple ID signed in to iCloud on your iPhone, then you would not be able to sign out without knowing the password for the Apple ID.

You can submit a request online to have the Activation Lock associated with the unknown Apple ID removed if you have the original proof of purchase. This process will also have the iPhone erased. Check out how to start the process here: How to remove Activation Lock - Apple Support

Additionally, you may want to ensure your Apple ID is secure by changing the password: If you think your Apple ID has been compromised - Apple Support

"If you think your Apple ID is compromised, use these steps to gain control of it and review your account information:

1. Sign in to your Apple ID account page. If you can't sign in or you receive a message that the account is locked when you try to sign in, try to reset or unlock your account.
2. Change your Apple ID password and choose a strong password."

If you've been added to an unknown Family Share group, then see if you can leave the group: Leave Family Sharing - Apple Support

"On your iPhone, iPad, or iPod touch

1. Go to Settings.
2. Tap Family. If you don't see Family, tap your name, then tap Family Sharing. 
3. Tap your name.
4. Tap Stop Using Family Sharing."

If further assistance is needed with investigating the behavior, then reach out to Apple Support directly using the following link: Contact Apple Support

Kind regards.

Hi DenisChernov,

Thank you for using the Apple Support Communities. You’ve posted a question in the English Community. If you are able to repost your question in English, you may reach a larger audience and have a better chance of receiving a reply.

Thanks!