Apple says: "When you make certain updates to your Apple ID, we’ll send you an email to help you complete the update. For example, you might have reset your password, reset your security questions, or added a new email address to your account." If Apple tries sending you a verification email and you do not receive it, read this support article --> If you didn't receive your verification or reset email - Apple Support
If you find you can’t sign in, reset your password, or receive verification codes, you can request account recovery (go to this document: How to use account recovery when you can’t reset your Apple ID password - Apple Support ) to regain access to your account. Account recovery might take a few days or longer, depending on the specific account information you can provide to verify your identity.
If you still need help this page provides country-specific Apple Support contact information ➞ Contact Apple for support and service - Apple Support