: https://swcdn.apple.com/content/downloads/62/38/001-68434-A_7C8SG92YKP/5izwryp0p5i53ihvhyb12j4h0clmnbck6x/InstallAssistant.pkg

hdiutil attach /tmp/Catalina.dmg -noverify -mountpoint /Volumes/Catalina

macOS Catalina - Technical Specifications - Apple Support (CA)

For advanced users, Apple's Software Update tool can be used via the Terminal to download specific macOS versions. While slightly more complex, this is a powerful and official method, particularly if you need a version not easily found in the App Store.

If you need help with a specific part of the installation, tell me:

Apple officially released macOS 10.15 Catalina in October 2019, marking a historic shift for the Mac ecosystem by dropping support for 32-bit applications and replacing iTunes with separate dedicated apps. Whether you need to revive an older Mac, set up a virtual machine, or create a bootable installer for troubleshooting, having a raw is essential.