Verification code location

If this is a location you receive,  about the time you were actually logging in, there is probably nothing to worry about. The location is where your ISP reported it. If their servers are in a location distant from you, there will be a large error. Based on other posts I have read, the distant error can be very large.

Check your Apple ID device list (https://support.apple.com/en-us/HT205064) and remove any device that shouldn't be signed in using the steps in the link.

If there are none that shouldn’t be signed in, then you should not have a problem at this point. But, if an unauthorized device signed in, Change your Apple ID password https://support.apple.com/en-us/HT201355 

Here is What to do after you change your Apple ID or password https://support.apple.com/en-us/HT204071

And see these security-related Apple Documents:

 If you think your Apple ID has been compromised https://support.apple.com/en-us/HT201303

Security and your Apple ID https://support.apple.com/en-us/HT201303

iCloud security overview  https://support.apple.com/en-us/HT202303

Ways to keep your information safe on Mac https://support.apple.com/en-gb/guide/mac-help/mh11402/mac

Using app-specific passwords https://support.apple.com/en-us/HT204397

kaan39 wrote:

Hello, my problem is this: When entering my iCloud account from the computer, a different city appears than the city I live in in the verification code that comes to my phone.

Are you using a VPN? Proxy server? This will provide a different location.