How to update my Apple ID

If you visit appleid.apple.com , you can change the important details of your Apple ID on the web. On iOS, tap your profile in Settings, and in System Preferences on Mac. Other important settings for your iCloud account are available on icloud.com .

What do you mean by " don't have lost the Apple ID"?

You can change your Apple ID email address on your current Apple ID so you retain access to your data and prior purchases. Note the restrictions in the article.

Apple ID Name Change.  * 

Make sure you turn off Find My Phone before signing out of the old ID. Once signed out and Find My Phone is off, then sign in with the new ID, then turn Find My Phone back on.

 What to do after you change your Apple ID or password - Apple Support  *  I suggest doing this before you change your Apple ID or password.

You need to change/add the phone number on your Apple ID. Look in the Security section when signed in online. You may have to add the new number before you can remove the old number. After the change, allow up to 24 hours for the change to sync. Before trying to make the change, sign out of Messages/FaceTime on all devices/computers.

Apple ID - Manage