iCloud id

The address which was created when you first opened the account - which would be @icloud.com, and also if you had the earlier versions, @me. com and possibly @mac.com - cannot be deleted or changed. If you created an 'email alias' additional address this can be deleted on the iCloud website by going to Preferences>Accounts, selecting the alias, and clicking 'Delete alias'.

Do you have two Apple IDs and want to delete one? If yes, see this read: https://9to5mac.com/2018/12/21/delete-apple-id-account/

Does the email address of your Apple ID end in iCloud.com, me.com, mac.com. One or two of these could be aliases for your Apple ID (depending on the circumstances), which implies the email address of your "official" apple ID is the remaining one. Of these options that are open to you, you can change your Apple ID officially to the one of your choice. Such a change is not very significant except for a very few circumstances. But, if you want to do so, see "How to change your Apple ID if it ends with @icloud.com, @me.com, or @mac.com" in this read: https://support.apple.com/en-us/HT202667 Use this read also to see other information about changing your Apple ID.

You other option is to change from an existing third party Apple ID to another third-party Apple ID. If interested in doing so, see "If your Apple ID is a third-party email address" in this read: https://support.apple.com/en-us/HT202667

In either case, see "What to do after you change your Apple ID or password:" https://support.apple.com/en-us/HT204071

In all cases above, I assume that you don't want to end up not having an Apple ID. I would never recommend not having one.

And, what if you think your Apple ID has been compromised? See: https://support.apple.com/en-us/HT204145

If you are talking about removing iCloud mail address from your iCloud.com account https://support.apple.com/en-in/guide/icloud/mm2a5932b3d4/icloud

Did you see my post above?