How to delete an Apple Account linked to an inaccessible email ID?

If you’re able to login you can deactivate from https://privacy.apple.com/, following How to delete your Apple Account - Apple Support. If not, visit https://getsupport.apple.com/solutions and select apple account to get help from apple support.

You are going to want to review carefully the information that has been provided to delete an account. If that account is currently signed into a device, you will not be able to remove it and would have to provide proof of purchase to remove the Activation Lock on that account.

You don't need access to the actual email address used for the original Apple Account. When you say you no longer have access, it is not clear if you no longer have access to that email or if you no longer have access to that Apple Account. If you forgot the password to that Apple Account, it can be reset even without access to the email address.

Just want to make sure you do not have that original account signed in on any device before deleting and that you realize that all data stored in iCloud for that account and any previous purchase of media and apps will be lost.

Also, you can also just update the Apple ID to a new email address that you have access to unless you are sure you want to delete it entirely from existence.

click here ➜ Change your Apple Account primary email address - Apple Support

Make absolutely sure all devices logged in to the Apple ID you wish to delete are logged out of it before you delete it because otherwise, they will be rendered unusable once the Apple Account is deleted.