I found this site a little while back, if you have a general knowledge of how master key systems work then creating a quick system is minutes away with MKCalc >> https://mkcalc.com/
Best of all it's free and fairly easy to use. You can save your system to their site but I usually print as a PDF to my computer. So far I've created a few systems with great results. It's not elaborate as some software but keep in mind it's free! Perfect for someone just starting out and can't afford some of the pricey software out there ....
Craig