This page instructs me to navigate to Settings > Business but this isn't a valid option in Quicken Classic Business & Personal. The page does not have any way to report incorrect information hence this discussion to try and get attention so it can be fixed.
https://info.quicken.com/sim/setting-up-your-business-in-quicken-business-perso#SettingupaBusiness-%E2%9C%85Method2:AddingBusinessLater