https://support.apple.com/en-us/HT211683 the link macOS Catalina does not download the package

Had to reinstall my iMac (failed drive and the time machine failed to restore) and after the install I was running Maverick now I am trying to upgrade to Catalina so I can reinstall my software which will not run-on Maverick. The problem is I can't find a link to install it.