While third-party sites often host "pre-made" ISOs, the safest way to get macOS Catalina is directly from Apple's servers to ensure the file hasn't been tampered with.
: If you are trying to upgrade a live machine instead of making an ISO, you can follow Apple’s official upgrade guide . macos catalina 10157 iso download new
If you don’t have a Mac to create the ISO, you might turn to third-party websites. If you do, follow these : While third-party sites often host "pre-made" ISOs, the
Once you have the in your Applications folder, you can use the Terminal to convert it into a bootable ISO: macos catalina 10157 iso download new
Run this in Terminal: