An Apple ID provides you access to all the Apple services on your iPhone, iPad, and Mac devices. A change my apple Id email in any of the devices can be seen on the Apple services on other devices using the same Apple ID.
If you have an email address that is no longer in use as your Apple ID, then you must change it with your new email address. Your Apple ID email address can be any third-party email address or an Apple email address itself.
But, if your Apple ID is a third-party email address, then you can change it with another third-party email address only. Similarly, you can change an Apple email address with another Apple email address alone. If you do not have an alias Apple email address, then there is no possibility to change your Apple ID email.
You can change your Apple ID email from either your iPhone, iPad devices, or from the Apple ID account page. Both of these methods are detailed here.
Carry out the steps given below to change your Apple ID’s email using your iPhone.