Getting old messages from a old phone number
What can I do if I change my number and I can't get access to my old phone number that's linked to my account? How can I get my confirmation code from my old number to my new one? I
iPhone 11, iOS 17
I assume here that you're talking about the iCloud account.
If so you can manage your information at appleid.apple.com
By the way, this community is about Numbers the spreadsheet application, not phone numbers, your inquiry is more appropriate to the Apple ID community.