How to change Apple ID email address
How do I change the email address associated with my Apple ID?
Question marked as
Top-ranking reply
Your Apple ID is the personal account you use with all Apple products and services. It includes the email address and password you use to sign in, as well as the contact, payment, and security details that you use with Apple.
You can’t merge multiple Apple ID accounts.
See this Apple article: Change your Apple ID
Change your Apple ID - Apple Support (SG)