What is my icloud security code

Read this document Set up iCloud Keychain - Apple Support

"If you're not using two-factor authentication, you might be prompted to create an iCloud Security Code—six digits, complex alphanumerics, or randomly generated—to authorize additional devices and verify your identity."

I have the 2 factor authentication but iCloud is asking for the security code as mentioned above. I've never seen this code so how can I obtain it to login into my iCloud????

I have the 2 factor authentication but iCloud is asking for the security code as mentioned above. I've never seen this code so how can I obtain it to login into my iCloud????