I want to change my icloud email

Do you mean your @icloud.com address? Once you have created an iCloud account and chosen an @icloud.com address to go with it you can't change the address (short of creating an entirely new account).

However, all is not lost. You can add up to three 'email aliases' - these are additional addresses (not accounts) which deliver into the same inbox as the main account. (In fact it's a good idea to give out alias addresses, rather than the main address, because if they attract spam you can easily change them.)

You should be aware before you start that once you've created an alias you cannot turn that address into a full iCloud account or move it to another account.

More information on aliases here: https://help.apple.com/icloud/#mm6b1a490a

Or do you mean the email address which forms the apple ID you use to log into iCloud? If this is a non-Apple address you can change it to another non-Apple address (provided thue latter isn't or hasn't recently been associated with another Apple ID) . Please see Change your Apple ID - Apple Support

You can edit personal information, including email addresses, by logging into your AppleID account at: https://appleid.apple.com