Change Apple ID and
I'm a freelance photographer. When I left the university to freelance full time I am using a Mac Pro (2017), it crashed. My friend reinstalled the Catalina system. So far it's been a disaster. Many apps are not compatible. Printers won't connect. iTunes doesn't recognize my Apple Id. Though I'm able to utilize (2021)Photoshop, Bridge crashes as soon as I open an external hard drive (formatted to MAC). Therefore freelance images are not accessible. He used his Apple id when he installed Catalina. How do I change his apple ID to mine?
iMac Pro, macOS 10.15