How do I change my iCloud Mail alias to a new one?

Tisiphone wrote:

I use an Apple alias email address for public news sites. Because of spam that it receives, I want to use a different alias. How is this accomplished?

Create a new one, and delete the old one if you wish to jettison it and the incoming spam. You can have up to three alias iCloud email addresses. In What are email aliases in iCloud Mail? Apple says that If you have three email aliases and you delete one, you must wait 7 days before you can create a new one.

Use email aliases in Mail on Mac will take you through the steps to create an alias address on your Mac.

You might also want to investigate Hide My Email which is another way of using a disposable email for non-personal reasons, and in this sense it would be a temporary rather than a long lasting email address.