I would like to change my iCloud email
If I understand things, you wish to walk away from the “old email” entirely - lose all cloud data, lose all purchases and make a new iCloud / AppleID on your new email.

If so, you’re going to need a few things and some luck or a call to Apple Support. Here are some limitations.


If your device is activation locked, you can’t walk away from the old iCloud - you have to recover that account. You will need to prove to Apple using a rigorous process (they will not deviate from the script, some steps will take days) if you can’t provide the security questions, receive a secondary email or remember and enter the password.
If your new email is associated in any way with the old AppleID / old iCloud you can’t use it for a new account or even associate it with a new account.


Assuming all of the above are OK, you would sign out of every iCloud using the old - all mac, PC, iPad, iPhone, iPod, Apple TV. Then you would set up your new AppleID - have it use your new email and then proceed to sign in on each device.