Forgot Password for Old Apple ID (prior to email address becoming standard)

I purchased a new iphone from Verizon. They transferred the majority of my information, but did not migrate many songs that I had purchased up to 20 years ago using my previous id, which was not my email address. To complete the transfer of that music, the system wants me to input my password from the very old id.

There was not an email address associated with the old id; it was simply a name that I had created.

How can I recapture the password for the obsolete id or reset it?