Change iPad Apple id
How do i change my Apple ID on iPad
iPad Pro 11-inch Wi-Fi, Cellular
Do you want to use a different ID or do you want to change the email address on your current ID? Use the first link to change the email address. If you want a completely different ID, the 2nd link applies to that also.
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.