can I change my Apple ID or consolidate?

Note the restrictions in the article.

Apple ID Name Change.        

 What to do after you change your Apple ID or password - Apple Support    I suggest doing this before you change your Apple ID or password.

mccando Said:

"can I change my Apple ID or consolidate? I'm stuck with a very long, very old email ID. want to tie it to my new(10yo) email."

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No. As of this reply, Apple IDs cannot be merged ("consolidated"). So, leave Apple Feedback on this.

Go Here: Apple ID: How to Provide Apple Feedback for this Category - User Tip