Q: I can't get keychain code.

Hello Efkan,

Thank you for using Apple Support Communities. 

I see you are trying to get your verification code, but you have a different phone number from when you set up your iCloud Keychain. Check the following from the FAQs about iCloud Keychain:

How do I set up iCloud Keychain on a new device without another device to approve from?

If you can't access any of your other devices that are using iCloud Keychain, you can still set up iCloud Keychain on another device if you have these items:

Your iCloud Security Code

The device that is using the SMS-capable phone number you provided when you first set up iCloud Keychain. A verification code is sent via SMS to this phone number. If you can't access this number, contact Apple Support, who can verify your identity, so that you can complete setup on your new device.

After you complete the setup, your iCloud Keychain will be pushed from the cloud to the new device.

Link to the FAQ: Frequently asked questions about iCloud Keychain - Apple Support

Regards,
Jeff D.