Update email address on ICloud
How do I update my email address on Icloud account information shown on my iPhone under settings?
Question marked as
Do you mean that you want to change the email address that you use for your Apple ID and iCloud? If so, see: Change your Apple ID - Apple Support
Also, be sure to note the following from that link:
Before you change your Apple ID email address, you need to sign out of every Apple service and device that uses your Apple ID. If you want to use your iPhone, iPad, or iPod touch to change your Apple ID, stay signed in to your Apple ID on just that device.