how to change subscriptions email

Are you wanting to change the email address on your current ID or create a new Apple ID?

To change the email address on your current ID, 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.

If you create/use a new Apple ID, you will lose access to some of your data and the purchases made with your existing Apple ID.

Apple ID - create a new.      

Apple ID – Create        

Apple ID - Could Not Create or Could Not Set Up iCloud message.