I changed my AppleID email address because my old address expired, and I can access it on iTunes, but whenever I try to log into iCloud from my MacBook it won't let me sign in under the new AppleID - the old ID keeps showing up. How do I change this??

Welcome to the Apple Community.

In order to change your Apple ID or password for your iCloud account on your iOS device, you need to delete the account from your iOS device first, then add it back using your updated details. (Settings > iCloud, scroll down and hit "Delete Account")

Providing you are simply updating your existing details and not changing to another account, when you delete your account, all the data that is synced with iCloud will also be deleted from the device (but not from iCloud), but will be synced back to your device when you login again.

In order to change your Apple ID or password for your iCloud account on your computer, you need to sign out of the account from your computer first, then sign back in using your updated details. (System Preferences > iCloud, click the sign out button)

In order to change your Apple ID or password for your iTunes account on your iOS device, you need to sign out from your iOS device first, then sign back in using your updated details. (Settings > iTunes & App store, scroll down and tap your ID)

If you are using iMessages or FaceTime, you will also need to log out and into your ID there too.

I had the exact same problem on my iPhone! It may be a little late to reply to your problem but hopefully it'll help someone on here because it really feels like a helpless problem to have.

I tried everything I could think of to fix this - I tried changing my Apple ID back to the original email address, I tried entering in the old password, resetting the password…anything I could think of. After an hour at Genius Bar and an hour on the phone with a lower level customer support rep, I got transferred to JOSH (who is the best person ever) who walked me through a few things and then finally asked me to try an "out of the box idea." He had me download the application FIND MY FRIENDS, which uses your iCloud login credentials to gain access to the app. By logging in, you're agreeing to the iCloud service agreement and by logging in to the app, it resent the ping (notification) to my phone that I updated my Apple ID email address and iCloud automatically updated my Apple ID to the new email address! I would have never thought that would have worked but it did. It turns out that this is a known sequencing bug in the Apple Software and when I updated my email address, it somehow forgot to notify my phone. It took less than 5 minutes to try this so if you're having the same problem or a similar problem, it's at least worth a try!!! Good luck!

I tried all the above, including Find My Friends. No luck!!

My PC worked fine (changed iTunes to new email) and so did my iPad. But my iPhone cannot seem to pick up that the new email has been verified.

The Apple website shows my iCloud and email are verified - but the iPhone doesn't see it. Even resend verification emaila nd tried to verify again. Still no joy.

Sorry I bugged out. Thank you for the help, that 5 minute trick fixed my sons phone.