delete old apple id

If you want to delete an apple ID you must have full access to it. (how else can apple know that it is the legitimate user requesting deletion)

If you forgot your Apple ID password - Apple Support

This article explains how to delete apple ID:

How to delete your Apple ID account – Apple Support

Good luck!

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.  Make sure you sign out from the places in the link before deleting the ID. If you fail to sign out of your device before deleting the ID, the device may become useless.

What to do after you change your Apple ID or password - Apple Support