I want to creat new apple iCloud email and I want to change

If you do not have an iCloud Mail associated with your Apple ID, then you can easily create one.

First, make sure you have the Apple Mail app installed.

Then go to:

Settings -> Apple ID (Your Name) -> iCloud.

Find Mail in the list and activate. You will now get the option to create a new iCloud Mail.

Once the new iCloud mail is created, just change your Apple ID mail from your old Gmail to your new iCloud Mail.

You can read here how to change your Apple ID:

https://support.apple.com/en-us/HT202667