Under what circumstances is the Apple ID, the Apple ID verification code will be sent to the mobile phone in the form of SMS.

If you turn on two-step authentication, you need a password every time you log in to your account. If you often receive AppleID verification code inexplicably, it is 100% stolen. But at this time, the thief knows your password but can't log in because he doesn't have a verification code for two-step verification! He tried to log in repeatedly, which is why you receive verification codes frequently. After enabling two-step verification of AppleID, Apple will provide you with an account security key. Don't save it in the computer. Take a piece of paper, write it down and hide it in a safe place where you can easily find it (preferably by memorizing it). If you want to change your password in the future, you must need a security key and an AppleID verification code to verify your identity. You can't modify your account unless someone else steals your mobile phone and security key at the same time. To sum up, AppleID must turn on two-step verification. No one wants to touch important personal information!