Hello RJAHJA,
There is a great support article that walks through the steps of what to do on all of your devices after you change your Apple ID: What to do after you change your Apple ID or password - Apple Support
For iPhone:
- "If you're still signed in with your previous Apple ID:
- Scroll down and tap Sign Out, then follow the onscreen steps. You might need to enter your password. Your data will remain in iCloud and will be updated on your device when you sign in to iCloud again.
- Enter your updated Apple ID and password.
If you updated your Apple ID email address* before signing out of iCloud, and your device repeatedly asks for the password to your previous Apple ID, you can temporarily change your Apple ID to sign in."
For Mac:
- "If you're signed in with your previous Apple ID:
- Click Sign Out. Depending on what iCloud options are turned on, you'll be asked if you want to make copies or delete iCloud data (Contacts, Calendar, Reminders, Bookmarks, Photo Stream) from your Mac. Your data will remain in iCloud and will be updated on your device when you sign in to iCloud again.
- Enter your updated Apple ID and password to sign in."
Cheers!