How do I get the same Apple ID on all of my devices
When I try to log into my iPhone's Apple ID on my MacBook, it says the Apple ID is in use, is there any way I can get all my devices on the same Apple ID?
MacBook Air
Can you sign into System Preferences/iCloud using the phones Apple ID? If there is already an Apple ID on the computer, have you tried using the article below as a guide?
What to do after you change your Apple ID or password - Apple Support