I can't disable two steps verification. There is no button "Turn off two steps verification" anywhere.

vduding wrote:

Please, help me to understand why can't I disable two steps verification from my Apple ID account. (It was created via iPhone with iOS 11). Thank you!

It sound to me like you are using "Two-factor authentication." Since according to your statement, "It was created via iPhone with iOS 11." According to: Two-factor authentication for Apple ID - Apple Support

"You can't turn off two-factor authentication for some accounts created in iOS 10.3 or macOS Sierra 10.12.4 and later. If you created your Apple ID in an earlier version of iOS or macOS, you can turn off two-factor authentication."

Because you created it in IOS 11.

"You can't turn off two-factor authentication for some accounts created in iOS 10.3 or macOS Sierra 10.12.4 and later. If you created your Apple ID in an earlier version of iOS or macOS, you can turn off two-factor authentication."

Two-factor authentication for Apple ID - Apple Support

See the following from Two-factor authentication for Apple ID - Apple Support

You can't turn off two-factor authentication for some accounts created in iOS 10.3 or macOS Sierra 10.12.4 and later. If you created your Apple ID in an earlier version of iOS or macOS, you can turn off two-factor authentication.

Keep in mind that when you turn off two-factor authentication, your account is protected only with your password and security questions.

To turn off two-factor authentication, sign in to your Apple ID account page and click Edit in the Security section. Then click Turn Off Two-Factor Authentication. After you create new security questions and verify your date of birth, two-factor authentication will be turned off. If you don't see the option to turn off two-factor authentication on your Apple ID account page, that means you can't turn it off.

If someone has turned on two-factor authentication for your Apple ID without your permission, you can also turn it off from the enrollment confirmation email sent to your Apple ID or rescue email address. Click Turn Off Two-Factor Authentication at the bottom of the email to restore your Apple ID to its previous security settings and regain control of your account. The link is active for two weeks after you enroll.

This is a user-to-user support forum. If you cannot turn it off and want to know why (i.e., an explanation for the first paragraph of the above article) you may want to contact Apple: Contact Apple for help with Apple ID account security - Apple Support