I need to add my new number to my Apple ID but I don’t have my old phone to get the code

You need to change/add the number on your Apple ID. 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     

 contact Apple ID Support for assistance.  See the Apple Support articles below for contact information.  

Apple ID - Official Apple Support.    

Contact Apple for help with Apple ID account security - Apple Support.   (Link doesn’t always load)  

Get Support          Work through the screens to get a chat option. You may have to pick a slightly different problem.

Starting an online chat with Apple Support

Apple Support schedule phone call

https://twitter.com/AppleSupport.          People have posted it may take an hour or more to get a response.