How to delete an Apple ID

All purchases made using an Apple ID are tied to the ID. Delete the ID and you will need to download them using your new ID. There have been posts by people who have contacted Apple Support and they were told that if you delete an ID associated with an email address, you can never reuse the email address for an Apple ID. Make sure you sign out from the places in the 4th link before deleting the ID.

How to delete your Apple ID account. https://support.apple.com/en-us/HT208504

Apple ID – How to Delete. https://www.imore.com/delete-apple-id

Delete Apple ID (new). https://privacy.apple.com/account

What to do after you change your Apple ID or password - Apple Support     https://support.apple.com/en-us/HT204071

There is no deleting you just don't use it.