Two-step verification code not received

You are not receiving the two-step verification code because your trusted phone number is not properly set or SMS delivery is failing. To fix it: check trusted numbers at appleid.apple.com, use “Didn’t get a code?” options, generate a code from another Apple device, use iforgot.apple.com for account recovery, ensure your SIM/eSIM is working, and contact Apple Support if everything else fails.

2-step verification/authentication of what? Apple ID, Google, Microsoft, Banks, etc...