Change Apple ID

Hello,

I don’t want a completely different and new ID because I want an additional or alternate email. I just want to change my name. My current ID is my former last name first initial.

I just want to use my new last name somehow someway. I can’t get beyond the first few lines on the Apple ID form.

it keeps rejecting my new IDs. Either I can’t use @icloud.com as an email address or the ID is invalid.